Only if they are listed separately in the uninstall window.

It is listed separately. I have tried over and over to uninstall it but nothing happens.

Let’s do a full clean re-install; Download Firefox For All languages And Systems {web link} Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86) Mac: Open the "Applications" folder.
https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory.

Do Not remove the profiles folder.

Look for, and rename any Mozilla or Firefox program folders by adding .old to them. Do not rename the Mozilla Thunderbird folder.

After rebooting the computer, run a registry scanner. Then run the installer. If all goes well, remove the OLD folders when you are done.

If there is a problem, start your Computer in safe mode and try again.

Starting The Computer In Safe Mode;
Free Online Encyclopedia

I am running Win 8.1 x64. Which download do I choose.....x86 or x64? or both?

You do not need both to use Firefox. The 64-bit Windows 7, 8 (8.1), 10 can run either the x64 (64-bit) or x86 (32-bit) Firefox while all other Windows users use the 32-bit Firefox option.

Note if you do use WIn64 Firefox only the 64-bit Flash Player and Silverlight is whitelisted to run. If you want to use other Plugins you need to use the 32-bit Firefox and 32-bit Plugins.