Boot Problems

Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS name,
nothing

should it display anything if we boot it with out a hard disc and no ram
installed
..
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare component
we have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but
mostly it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc


--
Nospam

Nospam wrote:
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS name,
nothing

should it display anything if we boot it with out a hard disc and no ram
installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare component
we have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but
mostly it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc


With the side off the computer, do you see the green LED glowing on the
motherboard ? Asus motherboards have a green LED, to show the +5VSB rail
is working. That green LED should never flash, and should remain on
steady as long as the rear switch on the power supply is ON.

When you press the front (soft) power button, the power supply fans
start to turn ? Are the system cooling fans working ? That would show
you've got some system power, but it doesn't tell you exactly whether
all rails are in spec or not.

The next thing to check, is whether the computer case has a small speaker,
and whether that speaker is connected via a connector labeled "SPKR"
to the PANEL header on the lower right hand corner of the motherboard.
You need that connection, to listen for beep error codes. Some expensive
computer cases, no longer have a speaker inside the case, which is a
nuisance in this situation. You really need a speaker for the next test.

To remove the RAM from the system, you turn off the power at the
back of the computer. The green LED on the motherboard should be
off, before working on the RAM. Otherwise, there could be standby power
still in the RAM socket. Once the RAM is out, turn on the power
at the back again.

When you push the button in this case, if you hear two or three beeps
from the computer case speaker (not the 5.1 speakers connected externally to
the computer), then that is a relatively good sign. For the computer
to beep, the processor needs to execute some BIOS code.

If, on the other hand, the "no RAM" test gives no beeps at all,
then you've got more serious trouble on your hands. The first thing
you'd check, is that the ATX12V 2x2 square power connector is still in
place.

For power connectors, you've got the main power connector (20 or 24 pin)
and the 2x2 ATX12V power connector. The proper ATX12V one has two yellow
wires and two black wires. Remove the connectors and check to see if the pins are
shiny. If the connectors were installed a bit loosely, without fastening
the retention latch on each connector, the loose connection causes the
pins to heat up and burn. Sometimes there is enough heat to melt plastic
and deform the connector. (I've only had one melt/burn here, but it was
a Molex 1x4 that had a contact problem, due to the manufacturing quality.)
Connector damage requires replacing connectors on either end, and
Mini-Fit Jr. pins might not be available at RadioShack for example. I
got some at my only good electronics store in town, but they don't
stock everything I need to do those kinds of repairs. But I did get
enough stuff to build my load box.

If you're not getting any beeps, and the two power cables are intact,
you have a couple ways you can go, based purely on frequency of failure.
If you had a spare power supply, you could install it and retest the
system. Due to the "capacitor plague" a few years back, where bad
electrolyte was used in capacitors, there have been a number of
power supply failures. I had an Antec PSU fail here, due to bad caps.

You can take a multimeter and verify the voltages on the main connectors.
These documents will give you some wire colors, pin names, and the like
to work with. But many people are not familiar with electronics, in which
case, replacing the power supply and retesting is another option.

http://web.archive.org/web/200304240...12V_PS_1_1.pdf

http://www.formfactors.org/developer...X12V_1_3dg.pdf

http://www.formfactors.org/developer...public_br2.pdf

Do motherboards fail "out of the blue" ? Sure. You could do a visual
inspection, for a burned regulator component, such as in the Vcore
circuits around the CPU socket. Look for bulging caps, burned MOSFETs,
or burned toroidal or square inductor packages. You can get any number
of pre-warnings, such as unstable operation (more crashes), refusal
to start reliably, a different "smell", a different background
noise coming from the computer case, perhaps a slight modulation
of what would normally be constant fan speeds. Any little hints like
that, help when trying to figure out what's broke.

If a different power supply isn't helping, then the motherboard would
be next. Install the CPU and heatsink on the new motherboard, and
do the beep test again, with no RAM or video card present. If it
beeps, then you know the old processor is working in the new motherboard.
If there is silence, then the processor could be dead. Processors
are relatively reliable, at least compared to power supplies, and
about the only kind of failures you'd normally run into, is a
processor throwing errors, soon after installation. Occasionally
a bad batch leaves the factory, but not that often. If you've had
the processor for a while, and it was fine, it isn't likely to
just "drop dead". (Exceptions, are applying extreme overvoltages
to your processor, while overclocking. But the overclockers know,
for particular processors, what is bad. For example, my E8400 is
not supposed to be run over 1.400 volts.)

At one time, AMD S462 socket processors were a bit flaky, due to
the lack of thermal protection. Some of those would "cook", and
when you disassembled the CPU and heatsink, you'd see signs of
overheating. But modern processors from both companies are protected
from overheat now, and the power supply will be shut off if the processor
gets too hot.

Good luck,
Paul

"Nospam" wrote in message
...
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS name,
nothing

should it display anything if we boot it with out a hard disc and no ram
installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare component we
have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but mostly
it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboarder issue could be the cmos battery 4GBytes DDR2
800MHz Ram
AMD2 CPU
320 GB SATA hard disc


--
Nospam

When turning on do you get a beep sound from the PC speaker? If you do then
the cpu, RAM and mb are working, and it could be a faulty graphics (even
though you substituted another one).

Another problem causing your problem may be a dead cmos battery. Remove it
and check the voltage. It should be around 3 volts. If lower then it's worth
replacing. On some computers having a dead cmos battery will cause a no
start problem.

Normally, even without a hard drive attached, but just graphics card and RAM
one should get to the bios screen, or at least a dos screen and halt notice.

Look at the capacitors on the motherboard. Is there anything liquidy
emerging from the tops of any of the caps, or at the base of them on the mb.
Leaking caps can keep the mb from starting.

If after pushing the on button it starts but then turns off that is a good
indicator of a bad power supply.

If you have two RAM chips installed try removing one of them and start the
computer again. If same error appears substitute the chip you removed for
the one that is left. RAM can cause boot problems as well. If no difference
then I would still go with the power supply.

--
Jan Alter

On 24/06/2010 1:04 AM, Nospam wrote:
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS name,
nothing

should it display anything if we boot it with out a hard disc and no ram
installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare component
we have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but
mostly it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc



Does the monitor display the OSD? If not, the monitor is dead.

--
spammage trappage: remove the underscores to reply
Many people around the world are waiting for a marrow transplant. Please
volunteer to be a marrow donor and literally save someone's life:
http://www.abmdr.org.au/
http://www.marrow.org/

Paul wrote:

Nospam wrote:
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS
name, nothing

should it display anything if we boot it with out a hard disc and
no ram installed .
I would have thought we would have a BIOS name then halt, I
wouldn't expect much with out ram but I would have thought we
would have got something.

we have changed the graphics card as that was the only spare
component we have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but
mostly it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc


With the side off the computer, do you see the green LED glowing on
the motherboard ? Asus motherboards have a green LED, to show the
+5VSB rail is working. That green LED should never flash, and should
remain on steady as long as the rear switch on the power supply is ON.

When you press the front (soft) power button, the power supply fans
start to turn ? Are the system cooling fans working ? That would show
you've got some system power, but it doesn't tell you exactly whether
all rails are in spec or not.

The next thing to check, is whether the computer case has a small
speaker, and whether that speaker is connected via a connector
labeled "SPKR" to the PANEL header on the lower right hand corner of
the motherboard. You need that connection, to listen for beep error
codes. Some expensive computer cases, no longer have a speaker inside
the case, which is a nuisance in this situation. You really need a
speaker for the next test.

To remove the RAM from the system, you turn off the power at the
back of the computer. The green LED on the motherboard should be
off, before working on the RAM. Otherwise, there could be standby
power still in the RAM socket. Once the RAM is out, turn on the power
at the back again.

When you push the button in this case, if you hear two or three beeps
from the computer case speaker (not the 5.1 speakers connected
externally to the computer), then that is a relatively good sign. For
the computer to beep, the processor needs to execute some BIOS code.

If, on the other hand, the "no RAM" test gives no beeps at all,
then you've got more serious trouble on your hands. The first thing
you'd check, is that the ATX12V 2x2 square power connector is still in
place.

For power connectors, you've got the main power connector (20 or 24
pin) and the 2x2 ATX12V power connector. The proper ATX12V one has
two yellow wires and two black wires. Remove the connectors and check
to see if the pins are shiny. If the connectors were installed a bit
loosely, without fastening the retention latch on each connector, the
loose connection causes the pins to heat up and burn. Sometimes there
is enough heat to melt plastic and deform the connector. (I've only
had one melt/burn here, but it was a Molex 1x4 that had a contact
problem, due to the manufacturing quality.) Connector damage requires
replacing connectors on either end, and Mini-Fit Jr. pins might not
be available at RadioShack for example. I got some at my only good
electronics store in town, but they don't stock everything I need to
do those kinds of repairs. But I did get enough stuff to build my
load box.

If you're not getting any beeps, and the two power cables are intact,
you have a couple ways you can go, based purely on frequency of
failure. If you had a spare power supply, you could install it and
retest the system. Due to the "capacitor plague" a few years back,
where bad electrolyte was used in capacitors, there have been a
number of power supply failures. I had an Antec PSU fail here, due to
bad caps.

You can take a multimeter and verify the voltages on the main
connectors. These documents will give you some wire colors, pin
names, and the like to work with. But many people are not familiar
with electronics, in which case, replacing the power supply and
retesting is another option.

http://web.archive.org/web/200304240...mfactors.org/d
eveloper/specs/atx/ATX_ATX12V_PS_1_1.pdf

http://www.formfactors.org/developer...X12V_1_3dg.pdf

http://www.formfactors.org/developer...2_2_public_br2.
pdf

Do motherboards fail "out of the blue" ? Sure. You could do a visual
inspection, for a burned regulator component, such as in the Vcore
circuits around the CPU socket. Look for bulging caps, burned MOSFETs,
or burned toroidal or square inductor packages. You can get any number
of pre-warnings, such as unstable operation (more crashes), refusal
to start reliably, a different "smell", a different background
noise coming from the computer case, perhaps a slight modulation
of what would normally be constant fan speeds. Any little hints like
that, help when trying to figure out what's broke.

If a different power supply isn't helping, then the motherboard would
be next. Install the CPU and heatsink on the new motherboard, and
do the beep test again, with no RAM or video card present. If it
beeps, then you know the old processor is working in the new
motherboard. If there is silence, then the processor could be dead.
Processors are relatively reliable, at least compared to power
supplies, and about the only kind of failures you'd normally run
into, is a processor throwing errors, soon after installation.
Occasionally a bad batch leaves the factory, but not that often. If
you've had the processor for a while, and it was fine, it isn't
likely to just "drop dead". (Exceptions, are applying extreme
overvoltages to your processor, while overclocking. But the
overclockers know, for particular processors, what is bad. For
example, my E8400 is not supposed to be run over 1.400 volts.)

At one time, AMD S462 socket processors were a bit flaky, due to
the lack of thermal protection. Some of those would "cook", and
when you disassembled the CPU and heatsink, you'd see signs of
overheating. But modern processors from both companies are protected
from overheat now, and the power supply will be shut off if the
processor gets too hot.

Good luck,
Paul

Paul,
I am one of perhaps several if not many "lurkers" here who devour this
forum to learn more about PCs. On behalf of all of us, I want to thank
you for an absolutely remarkable contribution you have been making to
provide clear, detailed, and thoroughly described answers to the wide
range of questions which people bring here for assistance.

Your range of knowledge is extremely impressive, and you have helped me
personally in the past with similar examples of extremely insightful
information, always focused directly on the pertinent points.

I know it is a big "risky" to single you out, since many others bring a
tremendous amount of very useful information to this forum as well, but
your replies have a special clarity, completeness, and depth of
knowledge which is really extraordinary. I do indeed thank all of the
other contributors as well.

I so very much wish that other forums and other contributors could use
this forum and your replies as a "model". It is rare to see such
courtesy, pertinent / relevant answers, and a lack of egocentricity,
and I, for one, applaud these efforts with great respect.

Thanks again for all of us.

Smarty

--

"Nospam" wrote in message
...
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS name,
nothing

should it display anything if we boot it with out a hard disc and no ram
installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare component we
have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but mostly
it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc


--
Nospam


Hi,

The Asus Crosshair motherboard has a small lcd display mounted on the back
plate. You can view it from the back of the PC case near the keyboard ps2
connector, it should give you some idea what the issue is.

Andy

In message ,
spodosaurus writes
Does the monitor display the OSD? If not, the monitor is dead.

Yes the monitor displays Acer Logo on switch on.

--
Nospam

In message f8FUn.25694$m87.7282@hurricane, Andy
writes


"Nospam" wrote in message
...
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS
name, nothing

should it display anything if we boot it with out a hard disc and no
ram installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare
component we have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but
mostly it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc


-- Nospam


Hi,

The Asus Crosshair motherboard has a small lcd display mounted on the
back plate. You can view it from the back of the PC case near the
keyboard ps2 connector, it should give you some idea what the issue is.

Andy

The display just says

Det DRAM

so its detected the DRAM but thats all it says.


--
Nospam

In message , Jan Alter
writes
"Nospam" wrote in message
...
Hi All,

My son's world has just collapsed!

His PC, home built has stopped working
After many year of use.

He has not added any new hardware, software or updates

It wont display anything on the screen at all. Not even the BIOS name,
nothing

should it display anything if we boot it with out a hard disc and no ram
installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.

we have changed the graphics card as that was the only spare component we
have.

Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display

occasionally we have had a few successful entries into the BIOS but mostly
it is a totally blank screen

I have measured all the levels out of the PSU and they are in spec.

why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.

Any suggestions most welcome

ASUS crosshair motherboarder issue could be the cmos battery 4GBytes DDR2
800MHz Ram
AMD2 CPU
320 GB SATA hard disc


--
Nospam

When turning on do you get a beep sound from the PC speaker? If you do then
the cpu, RAM and mb are working, and it could be a faulty graphics (even
though you substituted another one).


No speaker unfortunately



Another problem causing your problem may be a dead cmos battery. Remove it
and check the voltage. It should be around 3 volts. If lower then it's worth
replacing. On some computers having a dead cmos battery will cause a no
start problem.

The battery (CR2032) reads 3.15V using a Fluke DMM
so that looks OK.


Normally, even without a hard drive attached, but just graphics card and RAM
one should get to the bios screen, or at least a dos screen and halt notice.



Look at the capacitors on the motherboard. Is there anything liquidy
emerging from the tops of any of the caps, or at the base of them on the mb.
Leaking caps can keep the mb from starting.

No caps leaking, the mobo looks clean.


If after pushing the on button it starts but then turns off that is a good
indicator of a bad power supply.
I don't know if its turning off because it is being told to by the mobo
or if its detecting a fault internally and switching itself off.

Is they any way to check?


If you have two RAM chips installed try removing one of them and start the
computer again. If same error appears substitute the chip you removed for
the one that is left. RAM can cause boot problems as well. If no difference
then I would still go with the power supply.


We have 4 1GB ocz 800MHz DDR2 modules

we have tried each one singularly in A1 memory slot and the same problem
each time

we have tried it in various combinations of pairs.

Same issues

thanks for the suggestions



--
Nospam

In message , Paul
writes
Nospam wrote:
Hi All,
My son's world has just collapsed!
His PC, home built has stopped working
After many year of use.
He has not added any new hardware, software or updates
It wont display anything on the screen at all. Not even the BIOS
name, nothing
should it display anything if we boot it with out a hard disc and no
ram installed
.
I would have thought we would have a BIOS name then halt, I wouldn't
expect much with out ram but I would have thought we would have got
something.
we have changed the graphics card as that was the only spare
component we have.
Sometimes the unit switches itself off a few seconds after switch on
some times it stays powered but no display
occasionally we have had a few successful entries into the BIOS but
mostly it is a totally blank screen
I have measured all the levels out of the PSU and they are in spec.
why would it turn itself off?
Or is the motherboard turning it off because it is not functioning.
Any suggestions most welcome
ASUS crosshair motherboard
4GBytes DDR2 800MHz Ram
AMD2 CPU
320 GB SATA hard disc




Thanks for the very detailed response.
Much appreciated.

I have answered your questions in the text but as a quick summary;

I have tried the clr cmos button first with the cmos battery in place
and then without a batter in place but no joy.

the battery reads 3.15 V on my Fluke DMM

Also the beep test give the following
I fitted a speaker and get the following results

no memory
one long beep
followed by two short beeps.

With memory installed we just get one short beep.

After some measurements and checking of plugs we got it to boot, we
haven't done anything really, unless we had a suspect connection.

Also we only have two memory sticks in it, may be the other ram is dodgy

we ran it for 10 minutes and switched it off then we had trouble getting
it to turn on. The power supply would work for a few seconds then turn
off.

I tried this for a few dozen tries

I then unplugged 2 of his 4 fans from his 800 W PSU and was able to get
it to power up again.

I am starting to think it might be PSU related.

Some times it turns itself off after a few minutes of use (with the two
fans disconnected as described above).

I don't know if the PSU is being told to power down by the CPU/Mobo or
by internal PSU circuitry.

How do these atx PSU work



With the side off the computer, do you see the green LED glowing on the
motherboard ?

The LEDs that are glowing on the mobo are the 3 illuminated switches on
the mobo and one green LED

Power
reset
clr cmos

The green LED is near one of the slots, see next answer also.


Also there is a button on the rear of the unit that illuminates blue
LEDs around the mobo next to connectors, for easy of installing cards
etc.
But we dont have these switched on as it inhibits booting but they do
work so power is getting to the mobo.

Asus motherboards have a green LED, to show the +5VSB rail
is working. That green LED should never flash, and should remain on
steady as long as the rear switch on the power supply is ON.

This green LED is illuminates and is not flashing, solid green.


When you press the front (soft) power button, the power supply fans
start to turn ?

yes


Are the system cooling fans working ?

yes

That would show
you've got some system power, but it doesn't tell you exactly whether
all rails are in spec or not.


I have used my Fluke DMM to check the voltages on the 24 way connector
and they are all in spec +- 5%

The next thing to check, is whether the computer case has a small speaker,
and whether that speaker is connected via a connector labeled "SPKR"
to the PANEL header on the lower right hand corner of the motherboard.
You need that connection, to listen for beep error codes. Some expensive
computer cases, no longer have a speaker inside the case, which is a
nuisance in this situation. You really need a speaker for the next test.


No speaker unfortunately. But I improvised with a pair of headphones,
wow it was loud, think I might be deaf now ;-)

without any RAM fitted it is looping with
one long beep
followed by two short beeps.

The BIOS mobo manual does not list what the error beeps mean.

The LCD display on the rear of the unit says DET DRAM

no other clues.

To remove the RAM from the system, you turn off the power at the
back of the computer. The green LED on the motherboard should be
off, before working on the RAM. Otherwise, there could be standby power
still in the RAM socket. Once the RAM is out, turn on the power
at the back again.


When you push the button in this case, if you hear two or three beeps
from the computer case speaker (not the 5.1 speakers connected externally to
the computer), then that is a relatively good sign. For the computer
to beep, the processor needs to execute some BIOS code.

one long beep
followed by two short beeps.

With memory installed we just get one short beep.

If, on the other hand, the "no RAM" test gives no beeps at all,
then you've got more serious trouble on your hands. The first thing
you'd check, is that the ATX12V 2x2 square power connector is still in
place.

These are in place and read 12.54V, using a Fluke DMM
measure on the four green/yellow wires

The 8 pins inside the two 4 way connectors on the mobo all look nice
clean and very shiny

All the crimp terminals inside both 4 way square Molex type connectors.
They look tight not loose in any way.

No scorching or melted plastic.

For power connectors, you've got the main power connector (20 or 24 pin)
and the 2x2 ATX12V power connector. The proper ATX12V one has two yellow
wires and two black wires. Remove the connectors and check to see if
the pins are
shiny. If the connectors were installed a bit loosely, without fastening
the retention latch on each connector, the loose connection causes the
pins to heat up and burn. Sometimes there is enough heat to melt plastic
and deform the connector. (I've only had one melt/burn here, but it was
a Molex 1x4 that had a contact problem, due to the manufacturing quality.)
Connector damage requires replacing connectors on either end, and
Mini-Fit Jr. pins might not be available at RadioShack for example. I
got some at my only good electronics store in town, but they don't
stock everything I need to do those kinds of repairs. But I did get
enough stuff to build my load box.

If you're not getting any beeps, and the two power cables are intact,
you have a couple ways you can go, based purely on frequency of failure.
If you had a spare power supply, you could install it and retest the
system. Due to the "capacitor plague" a few years back, where bad
electrolyte was used in capacitors, there have been a number of
power supply failures. I had an Antec PSU fail here, due to bad caps.

You can take a multimeter and verify the voltages on the main connectors.
These documents will give you some wire colors, pin names, and the like
to work with. But many people are not familiar with electronics, in which
case, replacing the power supply and retesting is another option.

http://web.archive.org/web/200304240...actors.org/dev
eloper/specs/atx/ATX_ATX12V_PS_1_1.pdf

http://www.formfactors.org/developer...X12V_1_3dg.pdf

http://www.formfactors.org/developer...public_br2.pdf

Do motherboards fail "out of the blue" ? Sure. You could do a visual
inspection, for a burned regulator component, such as in the Vcore
circuits around the CPU socket. Look for bulging caps, burned MOSFETs,
or burned toroidal or square inductor packages. You can get any number
of pre-warnings, such as unstable operation (more crashes), refusal
to start reliably, a different "smell", a different background
noise coming from the computer case, perhaps a slight modulation
of what would normally be constant fan speeds. Any little hints like
that, help when trying to figure out what's broke.

If a different power supply isn't helping, then the motherboard would
be next. Install the CPU and heatsink on the new motherboard, and
do the beep test again, with no RAM or video card present. If it
beeps, then you know the old processor is working in the new motherboard.
If there is silence, then the processor could be dead. Processors
are relatively reliable, at least compared to power supplies, and
about the only kind of failures you'd normally run into, is a
processor throwing errors, soon after installation. Occasionally
a bad batch leaves the factory, but not that often. If you've had
the processor for a while, and it was fine, it isn't likely to
just "drop dead". (Exceptions, are applying extreme overvoltages
to your processor, while overclocking. But the overclockers know,
for particular processors, what is bad. For example, my E8400 is
not supposed to be run over 1.400 volts.)

At one time, AMD S462 socket processors were a bit flaky, due to
the lack of thermal protection. Some of those would "cook", and
when you disassembled the CPU and heatsink, you'd see signs of
overheating. But modern processors from both companies are protected
from overheat now, and the power supply will be shut off if the processor
gets too hot.

Good luck,
Paul

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