See:

• "Resetting the master password": http://kb.mozillazine.org/Master_password
• https://support.mozilla.org/kb/Forgot+my+master+password

You lose all stored passwords if you use the chrome URI or delete signons.sqlite and key3.db to reset the Master Password.

I use the password saver in Firefox, but I also keep a written copy in a safe place.

refer to

• Reset your Primary Password if you've forgotten it

and a quick tip....

Lock your computer when not in use, this ensures this doesnt happen again.

For Waka_Flocka_Flame , I do as well, the point here was looking for a way to solve the problem without loosing all my saved passwords, and having to re-enter them all again.

Sorry that would be a security hole and its impossible to recover them.

Thanks for your attempts at help, but I was able to finally figure out what the kids had done. It ended up not being that they changed it or entered one. The problem stemmed from a tool bar one of them installed, after I deleted it I was able to enter a Master Password and get everything back without loosing all my saved passwords. I have learned something from this however, I now have a copy of my key3.db file saved in a safe place so if anything happens in the future I have a back-up.

For Waka_Flocka_Flame, Your acidic responses were of no help at all, please go away.

Maybe you should lock your computer when not in use or if the kids share it use Parental Controls, sorry for being "acidic" in trying to help.

A copy of the key3.db won't help if signons.sqlite has been encrypted with a different encryption key than stored in key3.db.
You always need to backup both files (signons.sqlite and key3.db) at the same time to be sure that it will work.
If the Master Password changes then signons.sqlite is re-encoded with the new key.

Scott Remember to save the files every few days. There is a add-on that can help you called; FEBE. Best for the future. https://addons.mozilla.org/en-US/firefox/