To delete a registry key that contains an embedded null character, you must first replace the null character with another character. It is best to back up the Registry or create a Restore Point first.

Remove them from any startup scripts (Start->Run->Msconfig->Startup Tab), then try deleting the folders and registry keys.

However, if it’s the case that your account does not have the required permissions to open/modify/delete a specific registry key, you need to run regedit as SYSTEM account rather than an ...

I pulled up REGEDIT, and searched for keys related to ATI, and started deleting. Amazing how thoroughtly ATI pisses over the registry.