hi folks,
have an e-machines 130, 900mhz Celeron running windows XP that has
suddenly developed an error that i can't seem to fix.

When you boot it up it come up with the standard screen saying that
windows did not start successfully and offers the options of "safe
mode", "safe mode with networking" and "Safe mode with command prompt"
and "last know good configuration". it also counts down to autostart in
normal mode.

However, whichever option you choose it then goes onto a blue screen
with the following message:

a problem has been detected and windows has been shut down to prevent
damage to your computer.
UNMOUNTABLE_BOOT_VOLUME
if this is the first time you have seen this error screen, restart your
computer. If this screen appears again follow these steps.
If problems continue, disable or remove any newly installed hardware or
software. Disable BIOS memory options such as caching or shadowing. if
you need to use safe mode to remove or disable components, restart your
computer, press F8 to select startup options, and then select safe mode.
Technical information:
*** STOP: 0x000000ED (0x80E91E30,0XC0000032,0X000000000,0X000000000)

I have never come across this sort of error before and i am a bit
baffled. Is it a hardware problem or something with windows? unmountable
boot volume suggests hard drive problems to me but seemed unlikely.

Any advice you can offer that would point me in the right direction
would be greatly appreciated
Cheers
John