I have a home built system, and enough knowledge to make me dangerous in the system building world. I have an unusual problem though at the moment that's got me rather stumped. About 2 months ago, my PC started shutting down randomly and without warning. only seems to happen when running a particular game. Now, i've tried reinstalling the game, no help. Tried formatting the drive, comp seemed to run fine for 2-3 days then the problem returned. So all the drivers i have for all my hardware are very new. Finally figured the problem was over my head, and decided to take it to a shop and get a professional opinion. Among other things, i told him i'd checked all the ram, got the same shut down with each stick individually installed, ran a registry cleaner, scanned for virus' all came up clean. So i'm thinking it's over heating, put a 120mm case fan to blow right on the processor and ram, same problem still. The shop had the computer for about a week, when they finally called their opinion was the GPU. So, i pulled out the ATI 1650X gpu that was installed and put in a nice new Nvidia 9600GT. Here i am, 4 days after getting it back from the shop and putting in the new GPU, which is awsome, and i'm still getting the same random shutdowns. Also, about 3 months ago, my original power supply went out, so i put in a new 750w power supply. The shop tested that as well and said it was fine. So, i'm now officially out of ideas, aside from the CPU overheating, or the motherboard taking a dump on me, i'm completely lost on this one.