Hello howsue, in your system details it seems that you have in your [http://kb.mozillazine.org/Profile_folder_-_Firefox#Windows profile folder] a [http://kb.mozillazine.org/User.js_file User.js] file. The user.js file does not exist by default. If you create the file, forget it, if you have not create the file then try to delete the User.js file, to see if the problem goes away (some programs create the file also). thank you