Keypad not working at login

[KenK3]

My SP7 was working fine. I shut it down and then a few minutes later, I tried to boot it up again. The keypad suddenly stopped allowing me to type in my PIN when logging in. I can log in using the touchscreen and my numerical PIN on the touchscreen. Once in Windows 10, my keypad works normally. I have run the SP7 diagnostics, and it says all is well. I have cleaned both sides of the keypad contact terminals, uninstalled the keyboard drivers and restarted, and entered and exited the Surface UEFI. No help. The touchpad always works. The keypad LEDs always work. The cursor blinks in the login pin window, anticipating a typed entry. It's just that the keypad does not allow me to type my PIN in the login window.

 

[KenK3]

I re-installed, or did a repair, of Windows 10 today and it did not help.

 

[KenK3]

I wish I could tell you I found the answer, but it turned out to be another Microsoft "undisclosed product feature." In other words, it was something Windows 10 was doing. This morning, at sign in I got the option, under the sign in box, to choose the method I signed in, pin or password. It didn't like the password I have always used and made me change it but at least I now can use a password again.

 

[KenK3]

To add to the confusion, I just signed into my desktop computer running the same version and build of Win10 as my troublesome laptop, and it required my old password that contained a part of my email address in it. If I want to login to my Microsoft account, I need the new password I created because of my laptop. If I want to open Windows on my desktop, it demands my old password. Everything is working but don't ask me why or how.