Help: Password Not Recognized!!!

Yes. It never saw 10 until I owned it for several months.

Please jog my memory
You have a Microsoft account and the password ended up not working.
--- You were also using a PIN before but now the PIN option has disappeared
--- Now the Microsoft account password still doesn’t work even though it was changed.
On the “local account” is it still there upon your recent re-install.
--- Is it a local admin account or a standard account?
--- On that “local account”, was there a PIN in use?

BTW, when a PIN is in use, if I remember correctly, if someone wants to change their password, the PIN needs to be removed before changing the password.

It sounds like you still cannot log-in to Windows with either the Microsoft account or the local account.
--- Please verify.
--- I have a process that I believe will work for you to create an account outside of Windows that has worked for me on 2 computers.
--- It won’t help you on your Microsoft account but it potentially will allow you to log in to Windows: more information pending.
--- I’ll be glad to post it for you if the above is true.

OK as a reminder keep Caledon Ken’s post #11 advice handy
“I would use a Local account, then if you want you can migrate to MS account. When I set up a machine with a local Admin account I always add a second Admin account in case the first one gets Borked.”
--- I do that myself also.

Prior to the BSOD, reset, reinstall sequence, I logged into the local acct with my PIN and Safe Mode with my local PW.
The PIN option was gone. MS. demanded setting up One Drive, then demanded a PW change. Then my local acct. PW no longer works.

Review this article. I’m not an insider so I’m not familiar with what all of that article mentions.
Windows 10 Preview Product Key
Windows 10 Preview Product Key

Somehow, I suspect you were able to run your Windows 10 Insider w/o an official product key but that’s speculation on my part right now.
--- When you were running as an insider did you ever notice if Windows is activated was reported on your Control Panel > System page?

No, but the constant Windows Activation nag message is new with this incident. But: I ran SFC & DISM again, rebooted, and the nag msg. is missing from the lower right corner of the desktop where it has resided for several days. It showedup in my browser, too. The task bar was locked, I went to hide it, and got a notice that I must activate first!

The Windows Activation nag message is common on an inactivated system eventually.

I guess I’m missing a few more things so I need some clarification.
I was under the impression you couldn’t log into Windows anymore with either the Microsoft account or the local account due to password issues after your attempts to re-install Windows 10.
--- Your screenshot in post #25, shows that you are logged in.
--- Which account(s) are you logging in with? Either one or both?
--- Are you able to connect to the Internet?

According to Dell support, your system configuration was updated on 6/28/18.
--- What is the significance of that date?

According to this article
How long can you use Windows 10 without activation?
How long can you use Windows 10 without activation? - Quora
“Become a Windows Insider and you will have always the latest version of Windows 10 legally.”
--- What that tells me is if you can log into your Microsoft account for your Insider version, you’d be ok.
--- So that involves another question now:
--- When you upgraded Windows 7 to Windows 10, Did you immediately upgrade as an Insider?
--- However, if you cannot log into your Microsoft account due to a password issue, that needs to be done first.
When you can't sign in to your Microsoft account
https://support.microsoft.com/en-us/...t-sign-in-cant

Continuation, I hit a bad key combo
I can sign in but I can't run windows update, personalize windows, enter characters in the search in the Windows Store or set or start a timer. ProfoundSound C# has quit working. It said it could not start a vital service. The Svc said it could not run in Safe Mode, but I ain't in SM! I removed the program and it will not reinstall 'cuz it can't start the svc.

It is on the top of the case, at the rear. No other docs. This is not the first crash & clean install.