The user data is stored in the profile folder. You can copy the data manually by copying some files from the profile folder, for details see [http://kb.mozillazine.org/Profile_backup Profile backup - MozillaZine Knowledge Base] or [[Backing up your information]]. There are some add-ons and utilities that can make this process easier. The first one is the [https://addons.mozilla.org/en-US/firefox/addon/2109/ FEBE] add-on which can be used to copy a profile. Another option is the free [http://mozbackup.jasnapaka.com/ MozBackup] utility.