I'm experiencing a weird graphics problem!!

I have a weird problem where i have numerious polygons repeatedly flickering on my screen. It doesn't slow my game down and remove any textures just bother the hell out of me. It only started yesterday and I have no clue what caused it. I've tried a number of things:

-uninstalled drivers and installed latest one (84.21)
-reinstalled guild wars
-checked to see if card was overheating (50 degrees celcius)
-underclocked card to make sure it wasn't overheating
-did virus/adaware scans
-defraged pc aswell as tried to change setting in game with no luck
-made sure there was no dust in case and uninstalled MSN

I don't know what is causing this and I need help.

My system specs:

-AMD Athlon 2800+ Barton
-BFG Geforce 6600 GT OC 128mb
-1 gig ddr
-ASUS A7V8X-X series mobo
-Windows XP

I beg of you...help me cuz I can't play guild wars like this.
Theres a sample picture below:
There are HUNDREDS of these triangles/polygons flickering constantly...you can imagine how annoying it can get...

Can someone plz help me....I don't want this thread to just get lost in the heaps of other threads....I really need this fixed I don't want to be shipping for a new gfx card if I can fix it with a simple change.....

....well this thread is just getting pushed down further and further with no mods replying....i'm still waiting on a response

Try removing your video card. Make sure it's clean. Put it back in.

it looks like something is physically wrong with your card to me, perhaps overheating although as you said your temps are fine. i wonder though when did you check them? were you monitoring them in game or was that after exiting then looking?

Try uninstalling the video driver......if you have the same problem try installing new driver set.
A question: this happens only with GW or with others games?

Your problem is that your card is artifcating. This means that it is overheating as previous people have stated. Download Coolbits. Run the registry fix. Restart your computer. Open up your nVidia manager. And then place your card to 500/1000. Or 500/500 I forget if nVidia Doubles the RAM (1 time up 1 time Down. I'll check when I get back.) After this try it out, and see if you still artifact. Also, read the temp read out you get from the manager. Post up the measurement, while Underload.

As you've said already you've underclocked. There are 2 other things I can think of. The heatsink is not making proper contact with the chip, OR a transistor if overheating. Set it back down to vanilla factory settings, 500/1000. If that doesn't work, see if taking off the cover of your case helps, and maybe directing a fan towards the gfx card.

Also, eww mending+healbreeze