Cpu shut down coz of gears of war

hello,

i was playing Gears of war, after 15 minutes of gameplay, my computer shuts down automatically. Now, its not turning on! i keep on trying to turn on the CPU but failed. Finally I opened my case and found that only light on the motherboard is on and nothing is working - my power supply, my processor, etc nothing except this light!!!

now how can i solve this problem.....any suggestion anyone???


My configurations are:

ASUS P5KPL-AM/PS motherboard
Intel Core 2 Duo E7400 (2.80 Ghz)
SPARKLE (Nvidia Geforce 9400GT)
UMAX 450W PSU
Seagate 160GB Hard Disk
3 GB DDR2 Ram (1GB Kind\gston + 2GB Simmtronics)