Do you still see all extensions on the about:addons page (Tools > Add-ons; Ctrl+F1)? Do the extensions have an Enable button? You can check for problems with preferences. Delete possible user.js and numbered prefs-##.js files and rename/remove 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 current Firefox releases. *http://kb.mozillazine.org/Preferences_not_saved *http://kb.mozillazine.org/Resetting_preferences