Computer Overheating

[dlett822]

Hello,
I've had my rig for just under 2 years, and recently been having some issues with it. While running normally one day, my computer would randomly turn off. Using CPUID, I see that the hottest I am running on my GPU is 65 degrees Celsius and my CPU at 50 Celsius. However, it kept occurring, and the only way my computer can run without this happening is to have the case open and my tower fan blowing into it at maximum, yet the heat is relatively the same. It generally occured playing a video game (I play LoL, ABP and WoW mostly) or watching a justinTV stream Any help would be appreciated.
My rig is as follows:

Antec 900 case
core i7 920
Asus P6T x58 Mobo
EVGA GTX 470
Antec 1000w PSU
6 gig Corsair 1333 ram

 

[FunSurfer]

Can you check your PWM temperature?

 

[kikireeki]

It sounds like either the PSU or the mobo. Most likely the motherboard is failing. but it is better to try another PSU first.

 

[IH8U]

Suggest dusting the HS, and all fans first (spray duster, ~$5)(MOVE PC OFF THE FLOOR). Do you smoke? If so, refrain from doing so near PC's (tar buildup on the HS is nasty) and insulates it (a PITA to remove too).

 

[dlett822]

It seems the problem was the thermal paste. I replaced it and now my CPU is idling below 40 Celsius and I have had no sudden turn off. Thanks for the help!