See if this how-to helps. In this example, there is a dropdown box for the language, and then you click "Next."http://www.youtube.com/watch?v=FlxIvc16vQg
It's also possible there is a UAC prompt (User Access Control) hiding behind the window you're looking at, so if you see no way to choose or accept the language, try dragging the window around and see if there's anything hiding behind it.
If you need to uninstall the current ATI drivers, this video shows how to completely remove the current drivershttp://www.youtube.com/watch?v=ihVEGWrk5E4
None of this will help if the problem is with the card itself rather than the drivers.