9800 GTX freezing up!?!?

I recently bough a 9800 GTX from EVGA, and it has been working fine on my new computer. I downloaded Ntune, and i was messing with the fan speeds, and i guess i accidentally left it on 0% or something. So i am playing team fortress, and after 2 minutes the screen freezes, and it stops working. I then realized that the fan was on Zero, so i bumped it up to 80%. The problem is though, that the game is STILL freezing after a couple minutes of play. Running fraps, i am getting steady frames per second, then all of a sudden it just freezes and completely fails!! I know its not a network problem because i tried it on half life 2, and it does the same thing. I did not overclock it, and im pretty sure the temperature isn't a problem because it stay from 49 degrees to 56 degrees Celsius. Im not sure what to do!!! any help would be greatly appreciated!

probably overheated.

Well if it never froze before that then yes, its overheated and damaged.

You can use ATItool to heat it up and see if it artifacts. That's normally a hint that its dead.

Ever mess with the fan control. The card does a very good job in its own and will never let it self overheat(unless it runs out of fan speed, but that's unlikley)

Since its an EVGA you are covered under warranty i think. just say its freezing and locking.

With an older card, no fan would have survived, but new cards put out allot of heat.

On my girlfriends computer we use ATItool to place the card in 3d speeds(since it only uses full screen to trigger the 3dclocks) when running windowed games. It glitched and turned off the fan. After hours of games she checks the time and sees numbers overlapping in the system try. Bang 120c fan speed 0. Had to use RivaTuner to turn the fan on ATItool was not working. Thankfully the Accelero X2 cooler held the heat in check(120c is not going to kill that card) and the X1900XT can take lots of heat.

Anyway, try ati tool. If it sees artifacts the card needs to be replaced.
http://www.techpowerup.com/atitool/