Uninstall your current drivers, then use Driver Sweeper under safe mode to remove ATi driver leftover files from your HDD, then download and install the latest driver.
Are you using the driver that came with the CD?
Yes, I installed the drivers from the CD, originally, then I updated to CCC 11.5, it gave me no output (but I did have sound), so I rolled the driver from safe mode. Did this a couple of times.
I will follow through with your recommendations, and update the thread.