- move the messages to Local Folders to save them - delete the accounts

Thanks David, but it keeps wanting me to sign into the server before it will let me do anything.

but after you don't sign in, doesn't Thunderbird continue to run?

yes it's running but that account will not let me move messages. it keeps popping up a failed login box.

If all fails, - click help>troubleshootinginformation - scroll down to 'profile folder' and click open folder - exit thunderbird - click to Mail\account name (if POP) or to imapmail\account (if imap) - copy the folders to Mail\Local Folders - restart thunderbird and verify content. If all is well, you have successfully salvaged to data and can now delete the account.