A couple of options:

Use the password export add-on. For Firefox 2 you will need to use version 1.2 of the add-on, and for Firefox 4 you will need version 1.2.1 - Both versions are available from https://addons.mozilla.org/en-us/firefox/addon/password-exporter/versions/

With this add-on you can export the bookmarks to a file and then import that file on the other computer.

The other option is to do this manually. You need to do the following with Firefox closed on both computers. You will need to locate the profile folder (location where user data is stored) on both computers, for details of the location of the profile folder see http://kb.mozillazine.org/Profile_folder_-_Firefox

In Firefox 2 you need to copy 2 files, key3.db and signons2.txt, from the profile folder.

You need to place these 2 files in the profile folder on the new computer. key3.db will already exist, you need to replace it with the version from Firefox 2. There will be a file called signons.sqlite in the current profile folder, you need to delete that file.

When you start Firefox 4 it will create a new version of signons.sqlite containing the passwords from signons2.txt

Note that this method will delete any passwords that you have created whilst using Firefox 4. The first method will add the passwords from Firefox 2 to any that you have created in Firefox 4.

Thanks TonyE - the 2nd option worked great!

Please click the Solved It button next to the answer that solved your Firefox support issue, it appears when you are logged in, so this thread gets marked as Solved to help other users who may have this same problem.

I did do that but clicking on it does absolutely nothing. The mouse cursor does not change to the hand when over the button either