Hey this worked for me...after all that searching and stressing out over the problem the fix is so simple (without doing a custom install).
Detailed directions found on my blog:
http://danielpalmarin.edublogs.org/2009/12/01/catalyst-9-11-windows-7-bugs-fix/
Basically you just make a new ADMIN user account, then delete your old one by making it a standard user account + deleting it. You should be able to change your wallpaper again doing this (and fix some other issues). For for full details read my blog post (link above).
Detailed directions found on my blog:
http://danielpalmarin.edublogs.org/2009/12/01/catalyst-9-11-windows-7-bugs-fix/
Basically you just make a new ADMIN user account, then delete your old one by making it a standard user account + deleting it. You should be able to change your wallpaper again doing this (and fix some other issues). For for full details read my blog post (link above).
