colored splaches appear on monitor shortly after start up & screen turns different colors & freezes

About a minute after starting computer, red and purples spots appear on the monitor and sth escreen starts to studder turn colors and/or freeze. Occassionally random yellow pixels show up as well.

I was playing Grid and received any error message possibly about some file (from the little I was able to read) as the screenn flashed purple and green. This seemed to be the start of problem. However, the computer was set to shut off when I finished downloading something and shut right after the error message appeared. I was not able to read the error message.

I'm wondering if it is the video card or the monitor.

Any help is greatly appreciated.

 

it just started yesterday. I was able to get a cheap graphics card from best buy and that seemed To remedy the problem. So hopefully I can safely say it's the graphics card. My other card does have a lifetime warranty through EVGA so hopefully I can do something with that. If I do have to buy another card, can anyone recommend a good card for the $200-$250 range. Just from very little research I was thinking about the new geforce gtx 260. I'm the most likely looking for something that would give me great performance for my money and longevity as well.
Thanks guys

 

A HD4870 1GB would be better than a GTX260, and I would recommend that. The problem you describe is artifacting, which is highly suggestive of a faulty card.

 

The card I had before was an 8800 an 8800 320 MB. Would the ATI card a worthwhile upgrade if I could get a new GTS from the manufacturer to replace the one that broke and then sell the new GTS on eBay for about $100, and put that money toward the ATI card?

Also I have heard that the ATI performs better in racing games and things like that as opposed to the shooters. I don't play the shooters at all I play more of the racing games and the action action adventure type of games so I'm curious to know if this is true.

Would I be able to get quality performance out of the ATI card for about two years?

Thanks a lot for all the help.

 

ATI aren't necessarily better at a particular genre, but they perform much better on the GRiD / DiRT engine from Codemasters, which is probably the most demanding racing game engine currently available, so where the performance matters. That said, unless on a big screen, the game isn't very demanding compared to other recent titles.
Rough Relative performance index

8800GTS 320MB 100
8800GTS 512MB 140
HD4830 135
HD4850 175
GTX260 200
HD4870 220
GTX260 216 225
HD4870 1GB 230

As it stands now, the two games that have several absurdly powerful titles are FPS (First person shooter) and RTS (Real time strategy). Games like Prince of Persia are quite demanding, but nothing a 4870 couldn't handle. The main offenders outside the FPS genre are console ports, games originally programmed for the Xbox 360 or PS3 and then directly converted to the PC, not rewritten from the ground up. The worst of these are GTA4 and Saints Row 2, and Mirrors Edge.