Computer shuts down randomly (overheating?)

[UpsetTurtle]

Hello, as you can see im new so this may be the wrong spot, but it seemed to be the best place for this type of question. But anyhow my computer has been shutting itself off at completely random times whether i am using it, or it is just sitting there. I ignored it the first few times thinking maybe it was a fluke but now after several time (within a week) it is continuing to do some.

I ran Speed fan to see if that was the problem and i think it is. I was going to post an image but i need more posts, so here the info its displaying.
(Flame) GPU: 64C
(blue down arrow) Temp1: 36C
(blue down arrow) Temp2: 31C
(blue down arrow) Temp3: -128C
(blue down arrow) HD0: 29C
(blue down arrow) Core: 11C
(Flame) Core: 64C
(blue down arrow) Ambient: 0C

I also notice about every 5-10 minutes (only been running about 30 minutes) the GPU and Core (the one with the flame) are going up one degree.

Fan Speeds:
Fan1: 2368 RPM
Fan2-5: 0 RPM

I notice it says all but 1 fan are running at 0 rpm, i find this odd as i can see right now, the fan on the panel, the back of the tower, and the one attached to the psu (i think thats what it is) are all spinning. Any help would be greatly appreciated and if more info on my computer is needed i will post. THANKS

 

[Route44]

Heat will shut a system down fast. What are the temperature parameters for your video card?

 

[UpsetTurtle]

Well i have a Nvidia Geforce 8600 Gt video card. Couldent find the temperature parameters, but i may have been looking in the wrong place.

 

[UpsetTurtle]

Sorry for these two posts Aim was acting up on me

 

[UpsetTurtle]

Sorry for these two posts Aim was acting up on me