https://support.mozilla.org/kb/cannot-receive-messages

After checking the above settings from christ1 and making sure it all is working correctly. I now find I can send email, but not download email. Leading me to believe that some setting on my ISP's end is corrupt.

Anyone know where or how Thunderbird keeps the login information? I still have a good login info on my laptop, could I perhaps transfer that info from my Win 10 laptop to my Win 7 desktop to recreate the 'valid' login again?

You appear to have told us the answer yourself.

Tools|Options|Security|Passwords|Saved Passwords

Ah...that would be through Thunderbird itself. I was wondering where specifically I would find the file when using the Windows explorer. My goal, if possible, would be to transfer the password file from 1 computer to the computer that is missing the files (the ones I mistakenly deleted that compounded this whole mess for me) *very heavy sigh*

I think you are fighting your anti virus.

Thunderbird will ask you for any passwords it needs and does not have saved. You make no mention of that occurring, so I am guessing your anti virus is attempting to take over the world. This is a relatively common type of problem with product from Norton in particular, but any with a password vault type component. They save passwords and keep trying to use them. Even when nothing works because if it.

I appreciate your input Matt, but I did try your suggestion and disabled Eset Nod32 anti-virus and attempted to get email...to no avail. Seems that either something else is blocking my access to my email, or something else is wrong with Thunderbird. Funny this is this all started yesterday (Aug 27) on both machines simultaneously both using different versions of Microsoft O.S.

still scratching head over this anomoly

Found my answer.... my ISP does not require a secure login to download mail, just a secure login for sending mail. it appears that the last patch (45.2.0) changed my server settings on the Tools > Account Settings > Server Settings page. The Security Settings > Connection Settings were changed from None to STARTTLS, and the pop3 mail server was refusing connection. I didn't realize this until I found and read the Error logs and saw which error was showing up, which pointed me to the above situation. I just hope the devs community doesn't do this again, and properly leave a persons settings alone when an upgrade is performed.

It is not by design.

I am of the opinion that random changes to settings can and do occur, principally when upgrading Thunderbird. People lose toolbars, or find they are composing in plain text and not html, or find that security has either been enabled or disabled. I have lists of address books connecting them as whitelists to specific accounts, where things drop out now and then.