You have uninstalled and reinstalled Thunderbird. You used CCleaner to eliminate traces of a previous configuration of Thunderbird. You want to have no vestiges of the old data and older email account. How do you get clean start with Thunderbird (like an installation on a new workstation that has never had it)?
1. Open Thunderbird
2. Right click on an email username on the left (e.g., John Doe or firstname.lastname@example.org).
3. Go to Settings -> Server Settings and scroll down to "Local directory" where there is a field and a "Browse" button to the right of the field. Copy the contents of the field like this: C:\Users\jdoes\AppData\Roaming\Thunderbird\Profiles\blah.default-release\ImapMail\mail.foobar.com
4. Copy this text (of the path) in the field.
5. Close Thunderbird.
6. Browse to the directory that is the parent of ThunderBird (e.g., C:\Users\jdoes\AppData\Roaming\ ).
7. Delete the files therein.