GTX 295 keeps rebooting my PC

[remanz]

Guys.

this is not really related to wow. But I've been having this problem for a while now. When I run a graphics intensive games like FF14 (bad code maybe), or Call of Duty Black Ops (again, maybe bad code). My system keeps rebooting as if my graphic card runs too hot. Especially with the COD BO, there are certain scenes that would restart my PC every time when I hit it. But somehow the after burner (GPU monitoring tool) showed the temps are fine with the GPUs.

So my question is, how should I approach this problem. Would one of those GPU coolers help ? or there are some throttling utilities (or settings) that I can use .Maybe throttle the card everytime it runs too hot instead of rebooting it. The reboot will eventually kill my system if I keep this on.