Computer shut down, won't turn on

Lately my computer has been randomly shutting down, no error message no pop ups nothing, I searched on google for reason this could happen and I found some forums saying run chkdsk, I ran it and no errors were found, usually my computer would stay on all day except for when I go to bed and leave music playing, for 4 nights it has shut off over night, and sometimes during the day it shuts down randomly, I play World of warcraft, but it shuts down even when WoW isn't open so that can't be the problem, last night I went to bed and left music on, when I woke up the computer was turned off, I tryed turning it on and it wouldn't start, for some reason my fans work but the computer won't start up or make any sounds, I know its not the power supply because i've tested it and a friend told me chkdsk should have told me if it was my hard drive? I dont know what to do anymore....


don't know if it will help but


OS: Windows xp home
Memory: 2x 2gb
Video Card: EVGA 9600gt
Mobo: 4COREDUAL-SATA2

I've seen intel boards shutdown for CPU overheat, even when they haven't overheated. After a couple of times it would not even perform a bios post. I fixed the problem by removing the bios button cell battery for a couple of minutes, re-inserting, and then booting up and this fixed the problem.

Hope this helps.