With the power cord to the wall unplugged, remove and re-seat the card. Plug-in the power cord. Download Driver Sweeper here
and run it to remove all the ATi programs, drivers, etc. The Catalyst Control Center must have the MS .NET software installed before it can run. If you do not have it, including the updates from Windows update, download and install it. Re-start.Go to the ATi support site here
, download and install the software for your operating system and card.