USB Keyboard stops working after boot; can't ALT-SHIFT-S

I set up a system on an Insignia 8.9" tablet running Windows 10 Home . I used an external USB keyboard, followed all Windows recommendations. Windows did an update after, even though I had clicked "No windows Updates". Now when I plug the keyboard in so I can make a change to the system, the keyboard comes on at boot (I can see the NUM LOCK LED) then goes off before the Windows Login Screen. Secure Lockdown Standard Edition boots into the Master Application, which works. However, I cannot exit Secure Lockdown or make any changes, which are needed.

If you enabled the "System Lockdown > Machine Level > No New USB Devices" option, be sure the USB keyboard is plugged into the same USB port that is was connected to prior to enabling Secure Lockdown.

I read some of the previous posts on this issue. My device only has one USB port and I am using the same keyboard.

Somehow I managed to boot into my second admin account. What do I do now? Delete the Secure Lockdown account and start again? Will I have a problem with reactivation?

Is the system set up on the Inteset Remote Management Services? If so, you can disable Secure Lockdown from the console.

Try disabling Secure Lockdown using the method described under the "Hidden Secure Lockdown Features > Disable Secure Lockdown Using a 2nd Admin Account" section in the Administrator Guide.

No Remote Management Services, it's just a single device.

Can I just delete that user account and reinstall? I would prefer a known solution.

Or can I just uninstall the program from the 2nd Admin Account Control Panel? Any issues with that and reinstalling?

Also it won't be setup on Remote Management Services because it is used on a local WIFI with no Internet access.

So I deleted the problem user account... having read that somewhere else as a solution.  Now I can't access many Windows features (like display properties, system reset, etc) from the remaining account; I just get nothing.