windows vista home premium service pack 2 32-bit
intel quad core q6600 kentsfield socket 775 LGA @2.40ghz x4
memory 4gb : ddr2 ocz reaper edition PC2-6400 (400mhz) 2x2gb
mobo : Asus P5N-E SLI
gpu : nvidia geforce 9800 gtx+ gddr3 512mb
ive had this trouble for a long time , when playing online games (mainly cod4) at any time during play my system will instantly shut down (not re start or blue screen of death) just as if there was a power cut , i use the nvidia control panel to speed up my gpu fan during game play and i have a gpu temp monitoring tool and its never hot , i can keep the gpu running at 45c during game play so i dont think its the gpu , any suggestions to resolve this problem would be very helpful thanks .