Hello, I'll see if I can suggest some solutions.
First, you should open the computer case and examine the inside for any dust acclumulation, your problem might be a failed cooling fan, or dust buildup in a spot thats hard to see.
If you see dust its time to clean the case out and pay close attention to fins behind fans or the fans them selves for dust.
I suggest you also try making sure there is no oxidation on any of the connections of expansion cards verus the slot it is installed in, you can disturb this by removing the card and using a toothbrush in the card slot, just be careful not to lose pieces of the bristles in the slot.
Make sure your cables are secure and their connections are not affected by oxidation or corrosion buildup, which is commen with modular electronics circuits.
Make sure your BIOS settings for the hard drive was not reset, you should enter the BIOS setup and examine the settings for your hard drive, make sure it is the first boot device in the boot section.
Make sure your video card is configured properly in the BIOS as well, because an improper setting there could cause a system halt.
On your main BIOS screen see if there is a setting that says Halt on
then theres the choices of the following: keyboard errors, system errors, or no errors, change that to No errors
to see if the system proceeds to boot up.
One of the things people over look is looking in the BIOS utility for possible changes, perhaps even the BIOS battery has died and needs replacing, this will cause the system to fail to boot because the settings are now incorrect, as well as the system clock time and date being wrong, that's a dead give away the battery is dead. Errors from this can happen at a moments notice and is worth a look.
Before I make your head spin, please check the things I suggested and let us know if anything here has helped you.
Edited by MrBruce1959, 26 June 2010 - 02:24 AM.