Have you tried this;

• 1 Download Firefox Full Installer For All languages And Systems {web link}
• 2 Uninstall Firefox from your computer {web link}
  DO NOT remove your profiles.
• 3 After, reboot the computer. Then run the full installer.

I tried this yesterday and when I got on my computer today it had reverted back once again to an older version. Anything else I can try?

Please explain how you know it reverted back.

Also, check these out:

about:support

http://browserspy.dk/browser.php

https://support.mozilla.org/en-US/kb/find-what-version-firefox-you-are-using

https://jeffersonscher.com/res/jstest.php

I know because the little smiley face symbol in the top right of the screen goes away and when I check the what version of firefox I have it is one of the old 31.xxx versions rather than the 37 I had installed.

shpalmer86 said

I know because the little smiley face symbol. . . . goes away

What smiley face? Please do what I posted above.

What smiley face? The one in the chat cloud which is the symbol of the new in-broswer chat interface mozilla has added to Firefox. I have tried what you laid out above and it has not worked. Every time I restart or turn on my computer Firefox has reverted back to an older version. Nothing has worked so far to fix this issue.

Either you have both Firefox 31.0 and 37.0 installed and whatever method you are using start Firefox (say a desktop shortcut) after a reboot is pointing to the 31.0 version and not 37.0

Or something is reverting things to a earlier setup which includes Firefox 31.0 version.

Do you have security software that might be protecting files and folders?

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/

Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

• Download the Firefox installer and save the file to the desktop
  https://www.mozilla.org/en-US/firefox/all/

If possible uninstall your current Firefox version to cleanup the Windows registry and settings in security software.

• Do NOT remove "personal data" when you uninstall your current Firefox version, because this will remove all profile folders and you lose personal data like bookmarks and passwords including data in profiles created by other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other personal data are stored in the Firefox profile folder and won't be affected by an uninstall and (re)install, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall