Did you download your Firefox from Mozolla.org ?
Let’s do a full clean re-install;
Note: Firefox comes in three or more folders on all computers. They are;
Maintenance: (Programs Folder) <Windows Only>
Firefox itself: (Programs Folder)
And two folders in the profile of each user on the computer
for each Firefox profile for that user.
If you remove the Firefox folder, the user profiles would not be affected.
Download Firefox For All languages And Systems {web link}
Firefox ESR; Extended Support Release {web link}
Beta, Developer, Nightly versions
https://www.mozilla.org/en-US/firefox/channel/desktop/
Install Older Version Of Firefox {web link}
Be sure to read everything here.
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) Note: Check Both Folders
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;
https://support.mozilla.org/en-US/kb/install-firefox-linux
If you downloaded and installed the binary package
from the Firefox download page, simply remove the
folder Firefox in your home directory.
http://www.mozilla.org/firefox#desktop
++++++++++++++++++++++++++++
Look for, and remove any Mozilla or Firefox program folders.
Do not remove the Mozilla Thunderbird folder if there is one.
Do Not remove any profile folders.
After rebooting the computer, run a registry scanner
if you have one. Then run the installer.
+++++++++++++++++++++++++++
If there is a problem, start your Computer in safe mode and try again.
How to Start all Computers in Safe Mode; {web link}
Free Online Encyclopedia
Did you download your Firefox from Mozolla.org ?
Let’s do a full clean re-install;
Note: Firefox comes in three or more folders on all computers. They are;
Maintenance: (Programs Folder) <Windows Only>
Firefox itself: (Programs Folder)
And two folders in the profile of each user on the computer
for each Firefox profile for that user.
If you remove the Firefox folder, the user profiles would not be affected.
-----------
[http://www.mozilla.org/en-US/firefox/all/ Download Firefox For All languages And Systems] {web link}
[https://www.mozilla.org/en-US/firefox/organizations/ Firefox ESR; Extended Support Release] {web link}
Beta, Developer, Nightly versions
https://www.mozilla.org/en-US/firefox/channel/desktop/
[https://support.mozilla.org/en-US/kb/install-older-version-of-firefox?cache=no Install Older Version Of Firefox] {web link}
Be sure to read everything here.
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) '''Note:''' Check Both Folders
'''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;
https://support.mozilla.org/en-US/kb/install-firefox-linux
If you downloaded and installed the binary package
from the Firefox download page, simply remove the
folder Firefox in your home directory.
http://www.mozilla.org/firefox#desktop
++++++++++++++++++++++++++++
Look for, and remove any '''Mozilla''' or '''Firefox''' program folders.
Do not remove the '''Mozilla Thunderbird''' folder if there is one.
'''Do Not''' remove any profile folders.
After rebooting the computer, run a registry scanner
if you have one. Then run the installer.
+++++++++++++++++++++++++++
If there is a problem, start your '''Computer''' in safe mode and try again.
[http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode How to Start all Computers in Safe Mode;] {web link}
Free Online Encyclopedia