Video Card overheating?

Whenever i play a game, such as COD5, after about 30-40 minutes of playing the game freezes, glitches, the screen flashes and eventuall closes (or i restart my computer). If i start to play agian right after this happens it'll only take 5-10 minutes before all this happens agian.

I've opened up my computer and feel that the video card is pretty hot (i cant hold my hand on it for more than 15 seconds or so). Is there any way to fix this? Its getting pretty annoying, and i'd liek to play my game when i want too.

Lately, i've been playing on all low graphic settings and it doesnt overheat, or glitch out and the video card doesnt feel as hot as it does when im running full settings.

If its any matter its a NVIDIA GeForce 9800 GTX. The hole thing was a custom built computer.

As well, some people have suggested increasing the speed on my fan, how would i go about doing something like this? Im not sure if i feel comfortable taking the videocard out as i wouldnt really know what im doing.

Any help is appriciated, thanks

I downloaded this and am having a hard time figuring out where i can go to set the fan speed (not very computer literate )

EDIT: NVM, i figured it out after alittle looking. lol

Ill post back to see if this helps

Is this any downside to having your fan run fast besides the noise?