My last PC build was a Pentium 4 - 3 ghz machine. Recently, the pc has been randomly turning off. Usually occurs when my daughter or I am playing some online flash games. Pixie Hollow, Candystand, etc. What could be the cause of this. Is something overheating? I have an Nvida 128 mb card currently. Would it be worthwhile to upgrade the mb, ram, video on this processor or should I start new?