Hi HectoRocker4, please try about:preferences (without quotes), any luck ?

or, click the 3-bar menu in your top right and select Options to open the about:preferences tab

thank you

Start Firefox in Safe Mode to check if one of the extensions (Firefox menu button/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox menu button/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

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 personal data like bookmarks is stored in the Firefox profile folder, so you won't lose personal data when you uninstall and (re)install or update Firefox, 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.

If you keep having problems then create a new profile.

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

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

I recognize your response, but I didn't go through with it then, but after you proposed it, I went through the procedure until it worked. The Safe Mode did nothing, but re-installing Firefox after uninstalling it did it right! Everything, bookmarks and menu bar, came back after the re-installation. However, I did NOT have to manually remove the Firefox program folder(s) before installing that newly downloaded copy of the Firefox installer...the uninstall procedure did that already.

To ideato:

Q: Try about:preferences (without quotes), any luck? A: No, because I used the quotes as delimiters, so as to be clear (to say that I used about:preferences without quotes).

Q: Click the 3-bar menu in your top right and select Options to open the about:preferences tab? A: This didn't work either; in addition, I tried using the Menu Bar: Tools > Options...same result.

Firefox was corrupted, as it turns out!

Thank you, ideato, for your suggestions....