undoing autorun removal

The first time I came to this forum I found an post about the danger of autorun introducing malware to your system. It sounded legit but now I cannot access my USB drive. I did make a registry backup before I made the changes recommended. But even after I tried to undo the changes to the registry by running the backup file, I still cannot access my USB drive. :-o Can anyone tell me how to fix this problem? (short of reinstalling my operating system) Any help would be greatly appreciated.