I've found that many applications don't do a good job of cleaning up after themselves when they are deinstalled. I've often found many registry entries left over. It would be nice for ccleaner to search the registry looking for keys containing a particular keyword so they can be removed.
1. Uninstall software with an uninstaller such as Revo Uninstaller Free
2. To accomplish your search you can use NirSoft RegScanner (some antivirus' may falsely flag it).
Since I also use other nirsoft applications, I tried regscanner. It works really well. Thanks for the suggestion.