When you uninstall a Windows application, the uninstaller doesn’t remove all the files and registry entries created by the application. Sometimes the developers were too lazy or they thought those files might be needed if you reinstall the application. The end result is that your computer loads slower because your registry contains more entries and the hard drive stores unnecessary files.
Revo Uninstaller is a software that lets you completely uninstall programs and it’s easier to use than the built-in “Add or remove programs”. You can search for a program or locate it in a more intuitive way: enter in the Hunter Mode, open the program you want to uninstall and drag the target to your program’s window.
Read the article: Completely Uninstalling Windows Applications