The upgrade to Windows 10 1909 completed displaying the lock screen in blue with time and date in the left lower corner.
Clicking enter displayed the logon.
The password was entered and it displayed Welcome with rotating white dots.
Then the screen changed to black displaying Hi.
Then back to blue indicating there were updates:
This might take several minutes …………….Don't turn off your PC
These updates help protect you in an online world
Leave everything to us
Making sure everything is ready to go
It's taking a bit longer than expected, but we'll get there as fast as we can
Changed to black screen displaying: Almost there
Then only displayed a black screen with normal mouse cursor.
There was no Personalized settings or Personalized settings (not responsive)
Ctrl + alt + del displayed: Lock, Switch user, Sign out, Change a password, Task manager
Clicking task manger displayed a black screen with mouse cursor in the center of the screen with rotating blue circle.
The rotating blue circle disappeared and then it was back to a black screen with normal mouse cursor.
Task manager never launched.
There was no task bar.
Ctrl + alt + del > Clicking the power icon in the right lower corner then shift + restart > displayed choose and option: continue, troubleshoot, turn off your PC
Troubleshoot was clicked > it displayed reset this PC, and advanced options
Advanced options was clicked > startup repair was clicked > displayed a black screen > HP icon with please wait and rotating white dots > box flash > startup repair > choose an account > select main user account > entered password > Diagnosing your PC with rotating white dots > attempting repairs with rotating white dots > black screen with HP icon and rotating white dots > black screen with rotating white dots without the HP icon > black screen with normal mouse cursor > Getting Windows ready Don't turn off your computer with rotating white dots on blue background > blue background with rotating white dots > this had required a power off but I'll let it run overnight
Prior upgrade attempts to either Windows 1903 or 1909 only allowed the use of safe mode with command prompt. Safe mode and safe mode with networking did not work.
Using command prompt commands were able to be used to display text files or open some windows options: system info, msinfo32, dxdiag, event viewer, regedit, notepad, etc.
Prior upgrade attempts to either 1709, 1803, or 1809 produced error codes and messages.
I've forgotten what setupdiag displayed.