Loss of power to computer under stress

[Dangermouse]

Hi all

I built my own system from scratch about 18months ago and have been adding little bits here and their as different hardware becomes available in my price range. My current spec is:
Asus Crosshair NF590 motherboard
AMD X2 Dual Core AM2 Athlon 64 5200
4 gigs of Corsair XMS6400
Geforce 8800GT
800W power supply

I have had absolutely no problem with this setup for the whole time I have been using it until now. I have recently purchased Left 4 dead and every time I play it I get about 10-15 mins into it (usually during scenes of intense combat) and the computer just shuts down. It’s like someone has hit the power switch at the wall, No blue screen of death, no crashing sounds, just off. There is still power to the computer (all the LED lights are on) but my motherboard will not turn on again saying CPU INIT on the LCD display, until I turn the power off completely at the wall.

Could this be a hardware fault or should I perhaps try to update my bios? I have the latest graphics drivers.

Any help would be much appreciated.

 

[o1die]

Sounds like heat is building up somewhere. Could be the power supply, cpu, or video card. No easy answers here.

 

[Dangermouse]

thx, think that might be it. Just tried running the game witht the side of the case off and no problems. So i guess i have ventilation issues Thanks for the quick reply

 

[unclefester]

Can't remember for sure, but it sounds like your thermal relay in the PS is kicking out. If you r PS is not a top tier unit. After 18 months it may be getting weak.