Guild Wars causes "horizontal bars"?

Today I went to play guild wars, and at the loading screen, there were a ton of horizontal bars across the screen like: |_________||__________||_________|
and you could still see the background, but it was stretched out and kind of blurry. When I pressed the windows key, my actual background was like this too. I then closed Guild Wars and the bars were gone. I found this strange (has happened once before)...I was thinking that maybe I should reinstall Guild Wars because I might have a file missing or something.

Any help is greatly appreciated.

This is your video card. Sounds like its dying. Is it overheating? Check the heat with this app: http://www.lavalys.com
Go to Computer, Sensor, and then look for GPU Diode.

try playing another game that stresses your video card and see if it does the same thing.

also, what Leet Tankur said as well ........

I had a problem with white horizontal bars (don't know if you have the same problem) and after a long search i found it was caused by the "agp aperture size" setting in the BIOS. I changed it from 32Mb to 256Mb and my problems were solved. Hope this can help.

Also, make sure your video card is fully seated in it's slot.

Reinstalling the drivers sometimes helps.

Well, this has only ever happened while playing GW...I've played Aion and WoW and neither have done this.

If that is the case, re-install Guild Wars. Uninstall and download GW: www.guildwars.com/download

Then -image and re-downloaded the DAT.

I've had this happen to me before. Its likely something to do with an overheating video card.