System restarts on its own

[Gig-O-Ram]

It doesn't happen every time, but sometimes when I power on, my system will go through the boot process and make it to either the Windows boot screen or all the way to Desktop, and it will arbitrarily go into a restart and boot again. Then, after I get to the desktop, I get the message that says "Windows has recovered from a serious error". I've had it send the error to M$, and I've gotten explanations ranging from a RAM error to some kind of driver error. It's usually one of those reasons that comes up.

Windows problem, or HDD problem?

[polobunny]

Could be anything. Overclocked or not? If yes, either run some stability tests for countless hours or step it down a few notches if it only happens once a week.