I accidentally deleted ALL my saved passwords when I only wanted to delete

I always delete a password with the Delete key. If you do not have a backup of the files signons.sqlite and key3.db then your passwords are most likely gone. If you have used a Firefox 3.0 version then you may still have an old signons3.txt with passwords from that time. See http://kb.mozillazine.org/Password_Manager (Troubleshooting)

Thank you, I have resolved the problem.