Originally Posted by David Gill
I think it's an overheating issue, happened to me twice. And it can also be your drivers, have you updated them, go on the nvidia website and download then.
which games are you playing? Because if you're playing high end games your processor is not likely to cope with them.
I updated them right after the reformat, and just to be sure they are current, I updated them yesterday.
I generally play WoW, Dawn of War, and other random games, but nothing that is too graphics intensive.