Hello all, I used to own a Radeon 6770. One day about a week ago, the HDMI stopped working. The VGA worked so I used that and in my troubleshooting I realized that I could get sound out of the HDMI but not video. I thought it was the video card so I purchased a 7770. The problem is that I'm having the EXACT same issue. I didn't install anything or do anything else that could've messed with the system. Please help; thanks!
It could be the cord that you are using. Check the cord by using it on a different device and on a different screen.