Press the <Alt Key> to bring up the tool bar. Then Tools > Options > General.

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. Go thru the list and use a web search to check any that you don't know what they are.

Troubleshoot Firefox Issues Caused By Malware

there is no options for this

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

You can use this button to go to the currently used Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)