Okay well i have a Leadtek Winfast A400 GT (Geforce 6800 GT) and the card has been overheating pretty badly lately. I checked to see what the problem was and it seems the fan on the video card has slowed down a lot. Sometimes it even stops. So I was wondering if this could be a problem from the power supply or anything? Or if i should go get a new fan for my video card. And if i should get a new fan for my video card, could someone direct me to a fan that will be compatible with my card. Thanks for the help.

Check to see if your card is still under warranty from the manufacturer. If so, you might want to try to exchange it. If it's out of warranty, then by all means, get a new fan. I don't have a particular fan to recommend, however.

Sorry I can't exchange it, could someone suggest a fan that is compatible with my video card?

Have a look at the fan and heatsink at http://www.arctic-cooling.com/vga2.php?idx=40

I can't say for sure that it's the best one out there because I'm mainly into watercooling, but it's made of copper and comes with 6 years warranty from the manufacturer, so it can't be all bad. :)

Yes, the NV Silencer 5 is a very good cooling unit. I'm thinking about getting it for my 6800GT (idle 60C, load 80C).

Just make sure the fan that's in your card right now is clean and is not clogged up by dust. You don't want to buy a new fan and to find that the old fan is practically glued down by dust and would spin normally if cleaned properly.