It could be the work of one of your add-ons, or even add / mal-ware. Look thru your add-ons list and make sure you know what each one is there for. Also, check the programs that are on your computer

Windows: Start > Control Panel > Uninstall Programs. Mac: Open the "Applications" folder Linux:

• Ubuntu Unity {web link}
• Xfce: Applications Menu category sections
• options depends on the package manager and the desktop environment

Go thru the list. If you find something that you don't know what it is, use a web search.

Troubleshoot Firefox Issues Caused By Malware {web link}

All the addons other than Troubleshooter are ones that I've downloaded, so I don't think that's the problem.

1. First show the hidden files and folders:
   • Show hidden files (Windows Vista/7)
   • Show hidden files
2. Go to your profile folder:
   • How do I find my profile?
   • http://kb.mozillazine.org/Profile_folder_-_Firefox
3. Close completely Firefox.
   • http://kb.mozillazine.org/Kill_application
4. Delete or rename the localstore.rdf file.
5. Restart Firefox.

• http://kb.mozillazine.org/Localstore.rdf
• http://kb.mozillazine.org/Corrupt_localstore.rdf

You can check for problems with preferences.

Delete a possible user.js file and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in the current Firefox release.

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Resetting_preferences

Diego- I tried this, so I'll see if it works. I'll update you in a while.

Actually, I tried Diego's solution, and I thought it had worked, but I still have the issue.