Allright heres the problem:

My dads computer was shut down one night. He came back in the morning to boot it up and nothing happened (dead). Then he unplugged the lifeline and replugged - computer fans turn on and nothing else happens. BIOS never posts.

I had him listen for beeps, nothing. I even had him remove the RAM and listen for beeps, nothing. The 5V light is on when the lifeline is in, so I don't think it s the power supply. He also doesn't have a voltmeter to check the test points for +5. I can only help him over the phone.

Also, he says his mouse isn't turning on when in boot. I can't remember if the USB is slated to turn on after BIOS post (I'm assuming it is), if is supposed to be on then it could still be a power supply issue but I don't know. The processor was having overheating issues but I installed a new heatsink and it cooled a few degrees - even so the computer just shut off and now it only runs fans. Any ideas?