I had a 1900 crossfire card set up that was working great. Then one day my media pc card broke and I replaced it with one of my duel 1900 cards. I then got a new card for the media pc. So I went to return my crossfire 1900 card back to the gaming pc. Just in time for crysis =D All of a sudden I got blue screens and crashes with the gaming pc. I did everything i can think of to get it to work. I reinstalled vista and I even replaced the power supply with a 800 watt one. No matter what I do I can not get the the cards to run as crossfire anymore. I tried catylist driver 7.7- 7.10 with clean installs. It will only read one or both will come up as vga adapters. I also tried to plug the dvi on the second non crossfire into the first or the second plug in and get nothing but nightmare issues.