1. I don't see how can anyone answer that question without at least the name of the add-on. Firefox doesn't come bundled with any add-ons if you downloaded it from the official site at www.mozilla.org, or through the built-in updater.

2. Uninstalling from Control Panel and choosing "Delete my Firefox personal data and customizations" erases everything. If any shortcuts are left behind, right-click them and choose either Delete or Unpin from Taskbar.

Dear Gingerbread Man,

Thanks for reply. However, I clicked too quick. When I noticed a check box was checked, I did not have time to get the add-on's name, it started "update".

Immediately, I did uninstall firefox including "delete my Firefox personal data and customizations" . Two lines of firefox and Mozilla maintenance services were removed from control panel. However, firefox is still staying on taskbar and all programs in Start. That caused me to post a question to see if there is anyone had the same experience and/or know how to remove the firefox totally.

After noticed firefox is still exist, I ran Malwarebyte and Kaspersky anti-virus including rootkit scan. But all of the feedbacks were no threaten detected. Then, how come firefox is physically exist but invisible in control panel (I deleted it from control panel)? So, I do not know how to further delete the firefox from my computer.

That was the whole story.

SolutionSeeker1

Ok. The problem solved. I downloaded firefox and installed it again. It showed in control panel. Then, I uninstalled it. It removed totally from my computer.

SolutionSeeker1

Hi, what has worked for me to uninstall Firefox is as follows: firstly I have CCleaner on my computer from Piriform. I have it 'analyze' the situation and it says Firefox needs to be closed. It then asks to close it for me and I say 'yes'. It then asks if I want it to 'force' Firefox closed and again I say 'yes'. From there it does close Firefox. Then I 'run cleaner'. From there I go and remove Firefox and then restart my computer. I have tried to install earlier versions of Firefox and they still do not work. I am currently using 'Seamonkey' also by Mozilla and it seems to be working good. I also run CCleaner before I shut off my computer. Make sure it is by 'Piriform'. Hope this helps as it did me.

Thanks for reminding me to use Piriform CCleaner to make sure it is 100% removed the firefox browser. I will redo it to make sure the job is perfectly done. I appreciate your answer!

You are very welcome. Hope Mozilla can resolve Firefox as it is my favorite browser.

@SolutionSeeker1
Like I said, deleting the shortcuts was all you had to do. If you uninstalled Firefox, then it was almost certainly gone and you just had some shortcuts that pointed to a missing program.
The most likely explanation for the shortcuts remaining behind is that you created them manually. The uninstaller will only remove files that were created by the installer, not the user. You can enter the following locations in the Windows Explorer address bar to check that the folders are gone:

C:\Program Files (x86)\Mozilla Firefox
C:\Program Files (x86)\Mozilla Maintenance Service
%AppData%\Mozilla\Firefox
%LocalAppData%\Mozilla\Firefox

@bluewhaleotter
If Firefox was stuck running in the background, all you had to do is restart the computer.
If you have some other problem, like not being able to run Firefox, please see Firefox won't start - find solutions. If that article doesn't help, please start a new thread.