Thunderbird problem

[david]

This is not a Linux question but it is a FOSS related question.  I am running Thunderbird 2.0.0.23 under Windows XP.  Everything was working fine until I installed some extensions today and when I restarted Thunderbird none of my folders were listed on the left hand pane.  I can't see any of the emails that were there.  They are all still on my hard disk.  Trying to get mail or send mail through Thunderbird doesn't do anything.  If I look under account settings all of my accounts are there but I cannot access any of the mail.  I tried searching on Google but did not find anything that seemed to address this problem.  Any ideas or pointers to resources would be much appreciated.