See:

• http://kb.mozillazine.org/User_name_and_password_not_remembered
• http://kb.mozillazine.org/Password_Manager (Troubleshooting)

There are other things that need attention:

Your above posted system details show outdated plugin(s) with known security and stability risks that you should update.

• Java Plug-in 1.6.0_06 for Netscape Navigator (DLL Helper)

Update the Java plugin to the latest version.

• http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform: Download JRE)

If the above does not work you can go into internet options and reset via the advanced tab. There is also a wonderful program out there called Last Pass that will save all of your passwords. It is very secure and you only need to remember the admin password you setup. If you currently have passwords saved in Mozilla it will add those automatically. You could also try to uninstall and reinstall Firefox. Make sure you restart after you uninstall.

These fixes will not work if you are use Private Browsing...