Hi Phil, I've been using "Easycleaner" for years without any problems for cleaning the Registry,duplicate/unnecessary files, etc
It's FREE but you can make a donation if you wish to help the author.
Hi philkool, as VHG says CCleaner is free and it's good but there is a box somewhere on the download screen that when you click on it, it takes you to another site where you have to pay after it has done a scan. Just need to look carefully and click on the right box as it is with a lot of these things.