I recently bought a Dell XPS 420 Q6600 running Vista home premium 32 bit, 3 GB RAM. It came with a nVidia 8800GT video card which I replaced with a Visiontek ATI Radeon HD 3850. I'm using the machine as a home theater PC and I'm not much interested in gaming and the ATI card has better video decoding. I removed the nVidia drivers, swapped cards and then installed the ATI card. I then updated all the drivers for the card, got the most recent PowerDVD 7 update. The computer used to play Blu-ray's without difficulty but since I've changed cards PowerDVD 7 hangs when ever I try to play Blu-ray's - it plays DVD's without difficulty. Since receiving the ATI card I have spent about 4 hours on the phone with Dell tech support with their final recommendation to reload windows vista which I did. After doing this and getting all the drivers updated again the card still does not function properly – it won’t play Blu-ray discs and tech support has no further suggestions. I have also spent about an hour on the phone with the ATI tech support people also without benefit. It does not seem to me that this should be such a difficult problem. Any suggestions on where to go with this, I'm thinking that I should just go back to the nVidia card, but I understand that the ATI card is superior for video (I know that the nVidia card is better for gaming).