I had above problem with Catalyst Control Centre after downgrading AMD/ATI drivers from 13.12 version to 12.10 version. I have solved this by unhiding my user folder in C:\Users.
  1. Go to C:\Users and right click your user's folder. Pick “Properties”.

    2. Alter

  2. Check the “Hidden” box and click “Apply”. When prompted choose “Apply changes to this folder, subfolders and files”.
  3. After this operation is completed uncheck the “Hidden” box and again click “Apply”.
After it is done you should be able to properly launch the Catalyst Control Center.

If you, after downgrading your drivers, also have problems with running games and/or steam you can see this post.