All the settings you make in Firefox, like your home page, what toolbars you use, saved passwords and bookmarks are all stored in a special profile folder.Your profile folder is kept in a separate place from the Firefox program so that if something ever goes wrong with Firefox your information will still be there. It also means you can uninstall Firefox without losing your settings and you don't have to reinstall Firefox to clear your information or troubleshoot a problem. read how to backup your profile and restore it * http://support.mozilla.com/en-US/kb/Profiles you can always get latest version of Firefox from here * getfirefox.com

See: *https://support.mozilla.com/kb/Recovering+important+data+from+an+old+profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox