So my old laptop ran Windows Vista. While I upgraded to a new machine a while ago, it has taken me a lot of time to clean old files and photos off of it and transfer them over to the new machine.

My last hurdle which I was not expecting is trying to get e-mails that are in the Vista specific Windows Mail program off the machine into a format that that Thunderbird will recognize. The Vista WM can export but one format is basically Vista specific, the other is a format for Outlook which I never had on the machine to begin with?

Anyone have any good ideas that could work with this situation? It would be much appreciated!

I'd install Outlook then export to a PST and import on new machine (with Outlook).
However, what type of account do you have?
IMAP or POP3.
If IMAP the email may sill all be on your server and no import/export is necessary.
Could be the same even with POP3 if configured to leave messages on the server.
Don't know if there is a direct path to Thunderbird or not as I use/support Outlook primarily.

I know the e-mails are not on the server so that is out of the question. I have pondered trying to export in PST but where would one find a clean copy of Outlook?

I think I might sign up for O365 and do the transfer during the trial period.

Then migrate it to Thunderbird or just keep O365 (an pay for it).