I'm sharing this in the event the information may be helpful to someone else.

Today for the first time since I had the problems with loosing my windows installation, I opened thunderbird and tried to use its chat option.  The settings for a facebook chat account I use were gone.

Then I went through the procedure to create a new account.  I entered all the required information and clicked the enter button, but nothing happened.  Here's how I fixed it.

I backed up everything in my profile directory.  Then I deleted everything except the mail directory.  Next I started thunderbird.  First it recreated a bunch of file in the empty directory.  Then it asked me if I wanted to set up a mail account.  I closed that wizard and tried to set up the chat account.  I was able to.

I went to this site
http://kb.mozillazine.org/Files_and_folders_in_the_profile_-_Thunderbird
where there's a list of the files in a thunderbird profile directory and what they do.
From the backup directory I copied the files that contain the saved addresses (abook.mab and history.mab), passwords(key3.db and Signons.sqlite) and prefs.js which the site said contains all the mail server settings.

When I started thunderbird, my email accounts were there and so was the chat account.  It also let me add a new account.   I looked inside prefs.js and saw the settings for the chat account.  This tells me while prefs.js stores the account information, some other file is needed for existing chat accounts to be visible and new ones to be created.

Goodnight