Here's the thing about registry cleaners, they know less about your registry than you do, its best just to leave your registry alone and not play with it or let anything touch it. You have not been hacked it is simply that sometimes when a program uninstalls it leave certain registry values there because and again I stress this THE REGISTRY IS VERY FRAGILE
and again I will repeat DO NOT USE REGISTRY CLEANERS
they will do more harm than good. If you wont take my word for it have a look at this test done by another of the forums members dealing with registry cleaners: Registry Cleaner Tests - Why NOT To Use One!