HIS Graphics Card Problems

Hello,
I have a HIS HD 4870 1GBDDR5 Card installed in my home desktop that I purchased about 8 months ago. One month ago I was playing some Modern Warfare 2, and immediately after one session was loaded the screen turned all sorts of funny lines, and boxes appeared on the screen changing different colors. The system hung for a while than I got a BSOD Error and had to restart my computer. I restarted it and it worked fine until put under load. Same type of error. BSOD, system hang, sometimes I had to restart manually. After checking to see if the video card was seated properly and to check the connection in the 12v Rails to make sure they were plugged in correctly. Everything was looking good. Next day same thing after about 1 hour of play, screen goes wierd and BSOD again. This time after restarting my system, hard reset, the computer wouldn't boot at all. It hangs pre-post no active video out, monitor stays in standby mode. No Beep code NOTHING. I let it sit for a while, and try again. Nothing again. I let it sit even longer. Try to start it. This time, the computer doesn't do anything at all. Fans don't even spin. I'm really frustrated with this product and HIS in general. I've already requested technical assistance but no one ever got back to me. I believe it to be a bad video card. If anyone else has any suggestions let me know. I've put this card in two systems. The same problems happen every time. Another ATI card I have works fine in my home desktop leaving me to believe that it is the actual video card itself.

I'm running a 580W PSU should be plenty of power for one card.. The other system has a 680W. Any tips would be helpful, including tips on how to penetrate the wall between me and HIS's technical support group.

Thanks