This article will help you to transfer Firefox or Thunderbird from one PC to another or just help you to create a backup of these software.
To create a backup, you need to download and install MozBackup utility: http://mozbackup.jasnapaka.com/
Then, Install and run it and follow the next steps:
Choose the action you want to make:
If you want to transfer profile on another PC or to restore it, on step #2 choose “restore” and then choose a backup file.