Answer by Bernard for Uninstalling MiKTeX 2.9

I suppose you have a standard installation. Go to C:\Program Files\MiKTeX 2.9\miktex\bin\x64\internal\. Right-click on uninstall_admin.exe and select Execute as Administrator.

If you have MiKTeX 32 bit, go toC:\Program Files (x86)\MiKTeX 2.9\miktex\bin\x64\internal\.