Video card? Crashing

I have a problem with what seems to be my video card. This error does not occur while doing things such as using Word or browsing the internet. It happens every time that I get past the loading screen on World of Warcraft and occasionally while playing Counter-Strike source. My screen suddenly changes to this.
http://img95.exs.cx/img95/6853/glitched6fz.jpg
Does anyone have any idea why this would be happening? I have never overclocked my video card. Here are my system specs.
Motherboard: ASUS A7V8X-X
Processor: AMD Athlon XP 2800+
Video Card: Radeon 9800 Pro 128 MB
Monitor: Dell 1703FP
Sound card: Creative Sound Blaster Audigy 2 ZS
Hard drive: Western Digital 120MB
Networking card: Linksys Wireless G
Can you guys help me out? This has been happening ever since I got my computer up about a year ago, but now it is stopping me from ever playing a game. Thanks guys.
sh1ver
*EDIT* I have already tried reinstalling my video card drivers, reformatting my hard drive, and reinstalling both games, all to no avail.