In order to get the best results for your Radeon card, you should first
properly remove the old drivers from your system and then do a clean install of the latest drivers for your particular card.
It is never recommended that new drivers be installed over the old drivers without first
completely removing the old drivers. I don't know if you did that or if you
did uninstall the old drivers and then installed the new - but one unfortunate reality about graphic drivers is that the normal uninstall does not totally remove all the pieces of the drivers from a system.
1. First download the latest specific drivers for your card and your OS.
2. Then uninstall the old drivers in the normal manner.
3. Next, run the program that I provided in the link to completely remove all traces of the old drivers.
http://www.techspot.com/downloads/4266-driver-sweeper.html4. Once that is done you'll be asked to restart your system. After restart, launch the new driver install and follow the instructions.
5. After that is completed, you will have a clean install of the new drivers.
6. If all went well, go to the catalyst control center and there you will find the options for anti-aliasing, anisotropic filtering and a whole bunch more stuff to tweak your card.
7. If this still doesn't work then obviously something else is going on in your system configuration that is causing your issues.
Good luck and hope this helps!