For a safe cleaner use this it's free and safe as ccleaner is more destructive
WWW LinkFor a free auto registry backup tool use this,it's better than the joke that is system restore,well how many times you tried reverting only to be told no changes etc
WWW LinkBefore you clean use the windows clean up tool in control panel it's under performance and maintenance a defrag would'nt go a stray either, you can use ccleaner to erase any entries that are from uninstalled software usually ,MUI's,missing startup shortcuts,program shortcuts etc but becarefull with the other entries it will show if you don't recognise them leave em alone