Hello,Gary Gwynne-Smith
Thank you for posting in the Microsoft community.
Please don't worry, I'll work with you to figure out how to get the computer up and running as soon as possible. According to your description, it may be the problem of needing password when logging in after the recent Windows update, it may be the abnormality or corruption of system files brought by the updating process, the Microsoft development team attaches great importance to the problem you encountered, you can submit this problem through the Feedback Center, and it will let the engineers pay attention to your problem as soon as possible.
You can try to roll back the system version first.
- Press and hold the power button for 10 seconds to turn off the device.
- Press the power button again to turn on the device.
- Once you see Windows starting (for example, some devices display the manufacturer's logo when they restart), press and hold the power button for 10 seconds to turn off the device.
- Press the power button again to turn on the device.
- When Windows restarts, press and hold the power button for 10 seconds to turn off the device.
- Press the power button again to turn on the device.
- This time, allow the device to boot up completely.
- Select Advanced options > Uninstall updates or select System Restore
Or you can try the following to get into the system and create a new administrator account.
- If options such as "Ease of Access" or ""Accessibility" on the lock screen/login screen on your device are still available, content in the following thread described an idea summarized by a community member to reconfigure local accounts by temporarily replacing system components with Windows media. Locked out of PC by Windows 10 - Microsoft Community Windows Recovery CMD - Microsoft Q&A
Your home computer can use the above methods to reuse the system, but your work computer, if it has logged into your work account or connected to the company's network, is likely to be restricted by the company's group policy, if you need to resume normal use, it is recommended that you had better contact the company's it technician to ask if it will have any effect before proceeding.
If you have any questions, please feel free to contact me. Thank you for your understanding and cooperation!
Best Regards,
Rota|Microsoft Community Support Specialist