On one of the above messages I posted this link, http://kb.mozillazine.org/Tran.....underbird, it details what to do to move over from the old profile to the new one. I assume TB is now working correctly?
You'll find the different profiles in your DOCUMENTS AND SETTINGS folder for you UserID. I'm using W7, and the profiles are located here, C:\Users\Irv\AppData\Roaming\Thunderbird\Profiles, XP will be slightly different, if you open a command prompt, change to C:, and do a DIR PROFILES* /s you'll see it.
You can use Windows Explorer to look at the old one you had (dates on the contents will tell you which is the old one most likely) and move needed data files from it to the new one. You can also look in TB and note the location of the profile under TOOLS --> ACCOUNT SETTINGS --> SERVER SETTINGS on the bottom under LOCAL DIRECTORY...