Windows 10: Built in Admin login no long accepts my password

And, my user account went from admin to standard user after the two last updates. Now, I can no longer address the issue in Built in Admin mode nor can I do it in my standard account.

Please, please, tell me I don't have to reinstall windows 10? *LOL* If I do have to reinstall, I'll need to copy all my doc file again... right?

Oh and did I tell ya? The last update wasn't successful and I've no idea what happened.... *Sick

:)

 

THE BLACK SCREEN

Unfortunately I chose to upgrade to windows 10 and as happened to thousands of other users, the Black screen. Tried most of the solutions in forums but no luck. Cannot enter "safemode" or cannot select "back to previous built" as my admin password is not
accepted there. Cannot create new user, cannot remove login password. Driver updates, sfc scan, thirdparty fixes everything done.

any other solutions to 1. to remove black screen or 2. to login safemode or 3. go back to previous build?

 

Windows 10 admin login kicks me back out

When I try to log into my admin account from the login screen, Windows accepts the password but kicks me back out to the login screen.

OS: Windows 10 Pro

User account setup: admin account installs, etc. & standard user for normal operation

Steps:

1. Power on and reach login screen,

2. select admin account

3. enter password, hit enter.

Result - begins loading the profile then pops back up on the login screen.

Note: often launch applications using Run as administrator and accepts the password I have been entering is ok.

Ran virus/malware scans. Ran /scannow. Tried updating. Same thing.

Any recommendations?