I would just reinstall Thunderbird again. Windows has a habit of showing 2 versions installed. As you found out it is not accurate and by trying to clean up things you delete everything.

Thank you. I read another post stating that the actual emails are stored elsewhere. I found an older version of Thunderbird on my computer, reinstalled and all my emails are back. I've seen updated Thunderbird and everything's fine. It was a few hours of panic, but I've learned some valuable lessons...

Good reading! How to backup your profile. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data