CCleaner. Fixes registry stuff, clears all sorts of caches and has shortcuts to uninstall software, disable/remove applications from running on boot, disable scheduled tasks and delete/disable browser plugins/toolbars for most browsers all from the one place. And it's free. I'd honestly recommend avoiding literally everything else. Every other alternative I've seen has been crappy bundleware that works in a manner comparable to rogue security software. There are probably some decent alternatives out there but I'm yet to see one that comes close.
