What is your ATI graphics card? I should be listed in the Device Manager control panel, under Display Adapter.
You can download the latest drivers/Catalyst Control Center at:
http://support.amd.com/us/gpudownload/Pages/index.aspxThe latest version is 9.10. (The 9 means 2009, and 10 means the tenth month, October.)
The basic procedure:
Download the full package for your graphics card. (You don't really need the Catalyst Control Center, but I prefer to use it.)
Uninstall the Catalyst suite from the Programs and Features control panel. ("ATI Catalyst Install Manager" is the only entry, but you can remove everything - drivers, CCC, and the Install Manager itself, from the entry.)
Reboot.
Run the Catalyst installer that you downloaded above.
Reboot once more.
With any luck, that'll get rid of your problems.