Although, internet is bombard with registry cleaners but you have to end up somewhere. I have spent enough of my time downloading free registry cleaners. Out of many, i have tried registryrecycler, which actually turn out to be reliable software.
Go here to download it: www.registryrecycler.com/download.html
I use RegAce System Suite (http://www.regace.com) - it has a very good registry cleaner, a disk cleanup tool, a startup manager, an internet optimizer, a registry defragmenter and a service manager. All really good to keep computer in shape.