Did the 'New Account Wizard' come up?

New account set-up wizard comes up from shortcut & links that opened my existing Thunderbird account prior to 21 Oct 2017. I can see no way to get from that to open my existing account, folders, current & old emails. .. I believe all old Thunderbird files dating back to 2007, 2008 are still on my PC but there appears to have been an involuntary, perhaps automatic, update on 21 Oct 2017 which which has taken over existing links & shortcuts & prevents me from accessing my Thunderbird account.

http://kb.mozillazine.org/Recovering_a_profile_that_suddenly_disappeared

Just for the record, there is no such thing as a "Thunderbird account". You've set up an account with an email provider, e.g. Gmail or Yahoo. Then you use Thunderbird to access mail for that account on your email provider's server, as well as to send mail via your email provider's server.

Thanks. That's true I guess .. & it is also true that I can still get new emails by going to my email provider site. However, I still cannot access my previously existing Thunderbird set-up in which I have hundreds of folders & thousands of emails which I need to refer to from time to time. Many of them came via former email providers which are now defunct & the original emails no longer available. So I do need continuing access to the Thunderbird folders. Any idea how to open the Thunderbird set-up that I had prior to 21 Oct 2017?

Check the link posted above. I thought that's obvious.

Not quite so obvious to this aging brain which is, perhaps, not as quick, agile or perceptive as it used to be. A few years ago I would likely have solved this myself without the need for outside help.... I'm working through the steps in the link & have determined that profile folders & uncorrupt pref.js files are apparently still there. The step that I cannot seem to find in the MoxillaZine instructions is how to reactivate them when Thunderbird won't open. The instructions on how to get to Program Manager to switch profiles do not coincide with what I see (or don't see) on my PC & I have not been able to follow them.

So I'd assume you went ahead to the 'Lost profile section'. That takes you to the following article. http://kb.mozillazine.org/Moving_your_profile_folder_-_Thunderbird

You'd then following the steps as per section 1 'Use the Profile Manager to move your profile'. Is this correct?

If so, at which step do you get stuck?