Computer restarting on its own after 10-12hrs of use

bluntey

Honorable
May 5, 2013
40
1
10,530
Hey all, my GF's computer that I built for her seems to be having issues. After about 10-12 hours every night the screen goes black and the computer restarts on its own. I checked bluescreenview and it doesn't generate a .dmp file so its not actually blue screening.

There was a problem with the computer in the past. It wouldn't boot anymore for some reason with the gtx 460 in it, so I unplugged it and swapped in a gtx 260 and all of a sudden the computer started working again. The odd part was that the gtx 460 wouldn't work anymore in her computer but when I put it into mine it worked fine..

I'm guessing since its not blue screening that its most likely a power supply issue? Is it possible that it could be the video card or even the motherboard or CPU?

specs:
core i5 quad
asrock z75 pro
corsair 600W power supply
gtx 460 (now 260)

Thanks for reading.