Try to install FF another on it!!

Start Firefox in <u>[[Safe Mode]]</u> to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes). * Don't make any changes on the Safe mode start window. * https://support.mozilla.com/kb/Safe+Mode If it does work in Safe-mode then disable all extensions and then try to find which is causing it by enabling one at a time until the problem reappears. * Use "Disable all add-ons" on the [[Safe mode]] start window to disable all extensions. * Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit") In Firefox 4 you can use one of these to start in <u>[[Safe mode]]</u>: * Help > Restart with Add-ons Disabled * Hold down the Shift key while double clicking the Firefox desktop shortcut (Windows) * https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes ---- If that didn't help then do a clean (re-)install: * Download a fresh Firefox copy and save the file to the desktop. * Firefox 4.0.x: http://www.mozilla.com/en-US/firefox/all.html * Uninstall your current Firefox version and remove the Firefox program folder before installing that copy of the Firefox installer. * Do not remove personal data if you uninstall the current version. * 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. Your bookmarks and other profile data are stored elsewhere in the [http://kb.mozillazine.org/Profile_folder_-_Firefox Firefox Profile Folder] and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.