Graphics Crashing

Hi, thanks for helping =)
I've been having this problem periodically for several years since I got my computer. The problem is that periodically the video output for the game will go crazy, having lines through the screen and making it unplayable. 99% of the time it will happen in games and is sometimes repeatable when I enter certain areas. The problem occured in WoW, but I was able to fix it by disabling vertical sync in the game options. Just lately, the problem has been reproducable by loading up Civilization 4 and as soon as the game loads up into the actual Role-Playing Strategy Interface, the problem occurs.
I know that it's not the video card overheating, because I added an additional fan solely for the vid card. Also, since the problem has happened, I've replaced my RAM and motherboard to no avail. Also, when I first noticed this problem, I sent my video card back and got a new one, also with no luck.
Video Card- Radeon 9800 Pro 128MB
RAM- 2GB Patriot PC3200
CPU- AMD Athlon 2800+
Motherboard- ASUS A7V8X
Here is a screenshot of the problem occuring: http://allyoucanupload.webshots.com/v/2006117069758633390
I've never tried to overclock my video card or any other part of my system... any help would be GREATLY appreciated, this has got me frustrated past all ends.
~Charlie

 

Have you tried a different monitor??

Roger

 

Yep, I've tried a different monitor with no luck. I'm completely stumped.
~Charlie