The registry doesn't need to be cleaned.
How can you know whether or not the OP's registry needs cleaning?
Mine did this afternoon. MySQL 5.0 installer doesn't seem to understand how to upgrade a previous version, and the 4.1 uninstaller left some registry entries behind. Regclean didn't get all of them, disappointingly, so I had to delete the rest by hand before 5.0 would run properly.
(It would be
soooo much more straightforward if people who didn't understand how to write Windows installers and uninstallers would simply refrain from providing half-arsed versions, so that you would know from the outset that you were in for a tedious manual process.)