my saved mail folders have stars next to them

Can you explain that in more detail?

they are EMPTY!

See http://kb.mozillazine.org/Disappearing_mail

And how can I get them back???

If your messages cannot easily be restored you'll need to restore them from a recent backup of your Thunderbird profile folder you hopefully created on a regular basis.

Yes, Normally the folder list has: folder_name(number of unread)

Now most of them have: folder_name(*number)

When I look inside, some folders are entirely empty in spite of the large number. Others have a few entries, but not nearly the right number. -John