My PC Recently just statred losing power semi randomly and sutting down instantaniously now windows is logging off or any of that just straight to black a nice pop of the speakers and all pc activity stops. It usually refuses to boot back up for a period of time somethimes 4 minutes sometimes two hours. It will try and get to some random point and then just power down again. It seems to loose power mostly though not exclusivly when I have some heafty processes going on rather than when windows is the only thing running. I am running windows xp pro and recently reformated my hardrive and reinstalled windows but the problem persists. Is this my power source or somthing else suggested solutions please