There are several great programs out there called registry cleaners, whose job it is to scan your computer for obsolete and invalid files and folders and then allow you to easily remove them with just the touch of a button.  The best registry cleaner will also have a good backup and restore feature that will enable you to easily back up your registry.  This is very important beacause of the highly important and sensitive nature of the registry itself.  It’s kind of like the central nervous system of your computer and you don’t want to mess it up.