• Exit Firefox then navigate to your Firefox program folder and see if there is a Plugins subfolder. If there is, look in that folder for the leftover extension that did not get removed when you uninstalled it.
  
  
• If you're not sure which file in that folder is the old plug-in, right-click each file and select: Properties -> Description
  The description page will give you information about the file so you can tell if it's one that should be deleted. If it is, delete the file (you'll need Administrator permissions to do this).
  
  
• Restart Firefox

See also Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems and Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

If this answer has solved your problem, please mark the question as "Solved". This way you will help others in a similar situation.

Hello, Thanks for that. The plugin folder is "empty". In the extensions folder when I click properties there is no description option.

Have you tried enabling the extension, restarting Firefox and then checking to see if there is a "remove" button in your extensions list for it? There should be one there in any case, so if there's not, have you finished following the instructions in the help article above (Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems?

If so and the problem still occurs, create a new Firefox profile (see Profile Manager - Create, remove or switch Firefox profiles) and run Firefox with the new profile. Once you have migrated your bookmarks, settings, etc. to the new profile from the old profile, you can delete the old profile.

If this answer has solved your problem, please mark the question as "Solved". This way you will help others in a similar situation.

I guess the answer is creating a new profile (which I was thinking of doing but thought I would see if there is a magic solution). This addin is odd. I have uninstalled everything related to it but it keeps sitting in the addins list. There is no "remove" button whatsoever.

Yes, that is odd and indicates, to me at least, that there is something wrong with the way it installed. There is a method for surgically removing it, but is probably way too complicated for your purposes, and so just creating a new profile would be easier and faster.

If you run into issues importing your preferences from your old profile, there are other (less troublesome) add-ons that can help.