Happens to me with only a few games, lineage II, flatout, hitman 2. Now i can play games like doom 3 or half life 2 fine, but fable and etc just causes my computer at what seems like random to shut off with absolutely no warning. No video slow down nothing, just blip, powers off. It's not heat issues, the cpu stays steady under 40C and the case temp is always below 32.5C (videocard around the same as cpu). NVIDIA GeForce 6800(overclocked, but store bought oc (BFG)). On a asus(via chipset) motherboard. (also a 500w psu so i really hope that isn't it.) I have no clue what this problem could be. I've tried everything from installing more fans/spacing out my hard drives for better cooling/new heatsink/NEW CPU!!! the one i'm using is a replacement because of this problem(which wasn't needed)/updated drives/reverted drivers to old ones/swapped memory. nothing. Please help!

It could be caused by overheating or it could be a weak PSU. Just saying 500W doesn't mean a whole hell of a lot...a decent 350W unit is better than a cheap/crappy 500W unit. Generally, you get what you pay for in PSUs...a decent 500W PSU with at least 18A on the +12v rail would cost at least $50 ASUS A7N8X-X Athlon XP 1800+ 8.5 x 200MHz 1024MB PC3200 2.5-3-3-7 Asus A9550GE/TD 128MB WinME/WinXP Pro SP1

the reason your pc is shutting down is because your CPU is overheating, if you have a current motherboard made after 2000, then it is equiped with C.O.P. or CPU Overheating Protection, it automatically shutsdown your PC if the CPU gets to hot, frequent use of using computer at this rate will perminatly damage your CPU, i recommend u get a CPU Fan or liquid cooling......:) CyberPower 2.2 Ghz AMD Athlon XP 2800+ Overclocked 512 DDR400 PC3200 RAM Radeon 9600 Pro 256MB AGP x8 500 Watts Pwr Sony 52x32x52x CD-RW ROM Sony 16x DVD-ROM Sound Blaster Live!