One day you wake up in a spring cleaning mood and decide to delete apps that you haven't used in a long time or will never use again. Despite uninstalling from the system menu, most applications leave behind some files and folders. Do a thorough cleaning. You may need to manually check and remove any leftover junk in various places. Some of them involve deleting keys in the registry. So remember to make a backup before starting any changes. There are many utilities. They help remove programs completely, but if you want to do it without the help of a third-party application, that's how it is done.