OK - here is a very simple way to get around the problem which worked for me. As I read all of the comments, and did all of the “easy” checks of keyboards, etc. I realized this is problem with windows 10 updates, microsoft passwords, and completing updates. I wondered if there was a way to block microsoft. The only way I could think of was to make sure that the internet connection was turned off. That way your laptop is an “island”. When the internet connection was first turned off my password still did not work. Then I did a reboot from the settings on the password page. I immediately noticed the spinning circles again telling me it was working on an update. I got back to the password page, and put in my password. Instead of an error message, I got spinning circles for a few seconds - - and then I was in. Hit the “airplane” internet connection button, and you are back online all set to go. Hope this works for others.