If you accidentally checked the wrong box while installing Skype, you will have an extension in Firefox that you can’t uninstall. Sure, you can disable it. But what if you want to uninstall it?
You could completely uninstall Skype, and then reinstall it without checking the button, but there’s a simpler method.
Removing Skype Extension Manually
The first thing you want to do is go into Tools \ Add-ons and disable the extension if you haven’t already. You’ll notice that there’s no uninstall option, which is rather irritating.Skype is very useful, but don't want it in my Firefox.
Now close Firefox and open up a Windows Explorer window and browse down to the following location, adjusting if you installed Firefox somewhere else:
C:\Program Files\Mozilla Firefox\extensions
In that folder you’ll find another folder with the following name:
Just delete that folder and then open Firefox again. You’ll notice that the Skype extension is no more.