GrimReaper

Hi, i have a problem with my pc, it keeps shutting every program down on it's own... like when it wants to.... i have installed windows on it like 8 times in 3 weeks thats how bad it is... just wondering what the problem could be... and hopefully you guys can help.. i am running windows xp professional, service pack 2. i have a 1.73 ghz processor and 896 mb or ram and a 111gb hdd thanks GrimReaper (Dan)