I've built several systems from scratch but this problem has got me. Basically at random intervals (going from 30 seconds up to 24 hours +) the system will just shutdown. No warning, no error messages. Like someone pulls the plug. I have gotten all sorts of suggestions, but most of them deal with basically having a completely spare system to swap out parts with. I have been slowly working through my parts swapping them trying to figure out what is going on. System stats: P4 2.8 Ghz 1 Gb DDR ram, (1 - 512 Crucial, 1 - 512 Kingston, both 2700 working in dual channel memory) I have moved / removed these and it still seems to happen no matter the combo or even if they are single channel config. Running Memtest as I write this to get more details. EVGA geforce FX 5200 Ultra, 128 DDR GA-8Ik1100 Motherboard Running on 400 W Powmax powersupply on its own surge protector. Running WinXP Pro Temp. and heat are not a problem. The case is probably better air conditioned than my house. Everything appears to be connected well and it works fine while it is running. The only other info I can give is a suspicious shutdown it did just tonight. I slid the lid off the case somewhat banging the case while I did so and it shutdown. That seems damn odd since the connections are good. Also some memory intensive programs seem to cause it to crash and burn faster than just sitting idle. Any suggestions would be good. Thnx.