Hello, I recently was messing around with my ATI Radeon 7850.
Accidently, I hit the button for Composite sync in the Vision engine control, which caused the monitor to not work. I removed my GPU, and with onboard graphics, removed the current drivers for my GPU and updated them. Then, I put it back it, but now, in Vision Engine CC, my GPU doesn't appear there for me to change its settings and I still have to use the VGA in my Mobo, instead of my GPU's inputs.
More about :gpu showing amd vision engine control center