"twomt" wrote in message
...
Hello,

I fear I have a hardware problem somewhere, can someone give me some
hints on how to locate the root cause?

The computer is getting power as the fan is blowing normal and the
keyboard lights (caps-lock, num-lock and scroll-lock) blink once
when I press the power button.

Then it all stops, well... the fan continue to blows but nothing
else happens. This is before the bios screens come up when you
initially start your computer.

The monitor turns itself off saying it does not receive a signal,
the keyboard is not responding to anything (normally, num-lock would
show the light on/off) and my optical mouse is not showing the red
lights it normally does.

You say "the" fan is spinning. There is only ONE fan inside your
computer? Which one is spinning? CPU, power supply, case fan, what?
There should be 2 fans at a minimum: one for the CPU and another
inside the power supply (it must have 1 fan at a minimum but sometimes
it has 2 fans). Even if the PSU fan is thermally controlled, it
should always spin. Same for the CPU fan. If either of those are
stopped, you have a problem. The PSU fan is used as the minimal air
flow generator for your box. Besides cooling off the PSU, it draws
air through the case to cool the rest of the components. The CPU fan
must obviously be spinning to cool off this hot component.

When you power on the computer, do you hear it beep? After you see
the LEDs flash, several seconds later should be a beep which is the
BIOS telling you that the POST has successfully completed. An
internal speaker must be connected to the motherboard to hear this
beep. If you have an internal speaker hooked up and you don't hear
the beep then you might have to go to the last step where you revert
to a minimal hardware configuration to test your system.

Make sure the monitor is powered on before powering on the computer.
Some monitors deliberatly remain blank when they are first powered up.
If you use a power strip to power up all devices simultaneously then
the monitor may simply not be presenting you with a display to show
the problem before it gets cleared from the screen.

Does your startup of operting system generate any sounds, like an OS
startup sound event or beeps? I don't mean beeps from the POST
complete event in the hardware. I mean noises produced through your
speakers by sound events that you defined in your OS that you could
hear when the OS loads. If you hear those sounds then your monitor is
bad and why it always looks black although the OS really did load.
Before the system BIOS loads, the video BIOS loads first because,
well, you need to see the POST results. That's why the first thing
seen is the BIOS post from the video card at the top of the screen.
However, even before that the CPU pulses the reset line to ensure all
devices are returned to their base state which is why you saw the LEDs
flash on the keyboard. If the video card is bad then you won't see
anything regardless of successful POST and OS load. You say that the
monitor always remains black which makes it suspect because you
should, at least, see its post output at the top of the screen. Of
course, a bad monitor would also prevent seeing anything that was
being output by the video card. Check the cables between the video
card and monitor.

If you get to the POST screen (doesn't sound like it, though), check
the hard drive is working. When powering up, listen to the hard drive
(remove the side panel to hear the hard drive) which should exhibit a
whine noise as it starts to spin up.

Although you may not get to the POST screen, you can still clear your
CMOS by jumpering across the 2-pin header with a jumper. Leave the
jumper on for a minute and then remove (or leave attached by using
just one pin). If the CMOS gets corrupted then it may not allow the
firmware in the BIOS code to load because the parameters are too
screwed up. If that fixes your problem, you should replace the
battery.

Lastly, revert to a minimal hardware configuration. Remove power
plugs from all optical drives, all hard drives except the one where
the OS is installed, floppy drives, sound cards, data/fax modem card,
and everything from all the slots except the video card. The idea is
that you might have a failing PSU that can no longer supply the
current needed by the load from all the devices or one of them has
failed is causing the host to not boot. You should then only have the
PSU connected to the motherboard, maybe the video card, and a hard
drive. If it still refuses to boot to the POST screen, remove all
memory sticks but one and try again, and cycle through each stick at a
time if the host still fails to boot. I've had power supplies that
were high quality that still went defective after around 3 to 4 years
because of loss of voltage regulation (too much ripple) or could no
longer supply the amperage needed by the existing equipment which
hasn't changed. The PSU is the life's blood of the computer and way
too many builders go too cheap and rely on the specs which many PSU
makers stretch way too far for the capacity of their product. If you
get a cheap quality PSU then figure your max sustainable load will be
two-thirds of their rated wattage.