Nvidia Video Card locking up

My video card (I believe it's a Nvidia 6800, I know its Nvidia at least) has been freaking out on me when I have been playing World of Warcraft. It seems random so far. It's happened after 30 minutes or any time up to 3-4 hours.

Anyways, when I'm playing everything locks up and my screen turns into a pixelated mess. The best way for me to describe it is that it looks like a Robin's Egg, one of those malted chocolate easter eggs. The colors vary from pinks, blues and grays, but its always in a pixelated pattern. And the cursor turns into a block of the same color and pattern.

So far this has only happened when I have been playing WoW, but I haven't played any other video games on my computer recently. I have tried reseating my card, I air dusted it out (it was pretty dusty), and I reinstalled WoW. But the problem is still occurring. Anyone have any suggestions on how to fix this or know what might be happening?

Does sound like a Heat issue/High Overclock
Or the card could be dying.
I would take the card out and take the heatsink off and re-apply some Arctic Silver 5 Compound...it does get old and cakey...I redo mine 2X's a year.
You can also uninstall your Drivers with DriverCleaner Pro and reinstall...might be a corrupt file.
Hope this helps

I finally got some thermal paste yesterday and applied it to the heatsink and fan. Its seems to have fixed the problem (knock on wood) since it hasn't happened again.

Thanks for the advice Papa! (that sounded wierd)

Glad it worked
And thanks for keeping us up to date!!!
I guess in my first post I should have said Welcome to DEV
Hope you stick around and get to know some peeps around here...A Great bunch of guys if you ask me