To revert to the previous secure version, do this. Go to [http://www.mozilla.com/en-US/firefox/all-older.html Download Firefox v3.6.17] and download it to the desktop. Then go to Add/Remove Programs, scroll down to '''Mozilla Firefox''' and remove it, choosing to keep your bookmarks, customizations etc., (don't checkmark the box). Then reboot and delete the folder called '''Mozilla Firefox''' at this location: ''C:\Program Files\Mozilla Firefox'' Finally run the installation file you downloaded to the desktop earlier. Your bookmarks, customizations etc., are maintained in a different location and will become available to you again once you complete the installation. After you complete the installation, go to the [http://www.mozilla.com/en-US/plugincheck/ Plugins Check] page and update those if necessary.