Problems with ATI 9800XT

I just got my Dell XPS 3 weeks ago with the 9800 in it. Everything worked perfectly for the first two weeks. Then I started to notice some errors with the graphics in Battlefield: Vietnam. A few of the models would have some spikes sticking out of them. Over the next few days it became worse with more and more spikes until much of the screen was obscured by the spikes. Also, on startup at the Dell and Windows loading screens, there would be black or discolored rectangles on all the colored areas. When Windows finishes loading, there are several vertical bands about an inch thick that are pink in color. These cause discoloration when they are over lighter backgrounds. I had not made any changes when the problems occured and updating the drivers does not fix anything.

On the ATI website, it says that an RMA is necessary to correct blocks or colored lines in Windows. When I try to file for an RMA it says I cannot because the card is not a "Built by ATI" card. Do I return the card to Dell? If I do, how is this done?