Solved Advice Please - Win10 PC Corrupted So that I Can't Get Past Login

I am in need of help, please.
Background:
I have a multi-use home desktop tower PC with Win10 Pro, 8-months-old Gigabyte motherboard, 12th gen Intel i7, 32GB RAM, 1TB SSD boot drive, 2TB conventional data drive, MS-Office 2010 (yes - old, but fully functional), and many apps. I use Norton360 antivirus protection and Malwarebytes anti-malware. I never fail to apply any available updates. My only significant PC "sin" is the lack of a system drive backup image, mostly because I lack a drive with sufficient capacity. The data drive is cloud-backed automatically through Norton.

The BIG Problem:
A couple of days ago, I left a job running unattended. It was a freeware utility called Handbrake, merging a subtitles from a SRT file to a movie file in MP4 format. It was going to take 6 minutes, but I was too sleepy to say up and wait, so I locked the screen and went to bed. About 9 hours later, I unlocked the screen and found a big error window with a complex message about having run out of memory (no option to save details). Closed that, found that the Handbrake job had completed, but the app hadn't shut down, as it was set to. Shut that down. Tried playing the output file, but the player app didn't launch, even after waiting for quite a while. Read emails, closed down Outlook and the restarted Windows. That was the last time that I got to see the Desktop.
Now when the PC boots, the Windows Login screen appears normally, but no matter what is typed into the password field (even nothing), for the main User (=me), or the Administrator account, all that I get is "Welcome", with the rotating dot circle, for ever. I cant get past this point, no matter what I try.

Attempted:
WinRE recovery environment - just can't force this to happen, even with 3 or more interrupted boot sequences
Through bootable USB drive made on a laptop from Microsoft "Create Installation Media" web pages, I can access the Command Prompt

Thank you for trying.

This Forum seems t be limiting my ability to type a response to about 5 lines only, which is not sufficient for details. I've attached a text file.


If you can reach the cmd prompt then try these cmds:

Bastet said:

Code:

SFC /SCANNOW
DISM /Online /Cleanup-Image /StartComponentCleanup
DISM /Online /Cleanup-Image /RestoreHealth
SFC /SCANNOW

Yes the Sfc cmd is run twice.

Ensure you’re holding the on/off button to force restart as soon as the manufacturer’s logo shows.
You can als reach the recovery environment by holding shift while pressing restart on the log in screen, continue holding shift until the recovery environment shows.

Click to expand...

Bruce said:

Have you got another drive to use as the boot drive and install Windows from the USB stick onto.
Sounds like your 1TB SSD as died.

Click to expand...

Thank you.
From Command Prompt listings, the boot drive and all 3 other internal drives look fine, with all files and folders where and how I have seen them before.

PeterOz said:

Boot from the usb you made and try the repair on the setup screen.
Your data and programs should be safe but there is never a 100% guarantee.
View attachment 13708

Click to expand...

Yes thank you, this is exactly what I get from booting on the USB media, and how I get to the Command Prompt. All the other functions offered by "Repair" (fix inability to start, restore point, undo updates) do absolutely nothing, and then just suggest that I shut down my PC. How very useful. Why oh why did Microsoft remove Safe Mode...

PeterOz said:

To add safe mode to the boot menu​

Choose to boot the computer from usb

At the first setup screen click on next

On the install screen choose Repair your Computer

Click on Troubleshoot

Click on Command Prompt

In the Command prompt window change directory to your windows drive

Example

At the X:\Sources>E: Press Enter

At the E:>cd\windows\system32 Press Enter

At The E:\Windows\System32>bcdedit /set {bootmgr} displaybootmenu yes Press Enter

You should get a success message

At The E:\Windows\System32>Exit Press Enter

Click on Turn Off This Computer

REMOVE THE USB STICK

Power on the computer

You should now have the option

Press F8 for safe mode

Click to expand...

Thank you.
Unfortunately I didn't get the "success message" to the bcdedit command.
Screen image attached.

I'm not used to interacting with Forums. Please have patience with me. Believe me: I'm more frustrated by this problem than you are.
Results are in the attached screen photo.
Thank you for trying to help me.

Hi.
Sorry to be a continuing disappointment. The first operation didn't complete successfully.
Screen photo attached.
Thank you again for trying.

bcdedit

diskpart