im trying to fix my wifes pc. its all ****ed up so i was going to re-install windows but when i try to install windows xp it just shuts the pc down and it dont just shut it down i have to turn the power supply off then turn it back on then i can turn the pc back on. i have put another power supply in and it still dose it. also if i just let it go into the fubared version of windows it will run for days without shutting off. i can play graphics intensive games and it will run and not shut down so its not overheating. i have also cleaned the dust out of it as well.