Not sure if this is the right area to post this, but I just bought a new case, (haf 932) to replace my old one, and now after switching everything, I can't get any video. I'm also not getting any error beeps, so I know I must be doing something wrong.
I'm using a 4830 on a gigabyte ex58-ud3r motherboard, if that matters.
The most likely problems are either you forgot to re-connect a connector or you have a short somewhere with the new case. The breadboarding suggestion at the bottom of the checklist is to rule out a short.