I decided to upgrade the graphics card in my brothers PC today and now it won't boot properly. The computer starts like normally with the fans and lights all turning on, except no sounds are made. The monitor (and we've tried two, which both are working fine on my pc) wont even recognize that the pc is connected. We took apart all of his components in case any connections came loose replacing the card, and that didn't help. We've now tried with the old one, and with none at all. Unfortunately I can't find out how to fix the problem. Sorry for the long explanation, and thanks for any help.