Win 10 login problem since last update.

Instead of getting the small window that allows me to enter my password number to login I now get a message saying there is a problem and the window is not available.
There is also the option to reset the password, so last night I clicked on it, but then a warning came up saying if I reset the password I might have problems logging into various websites, so I cancelled and miraculously was logged in anyway.
Same has just happened, so I took the microsoft account login option which went smoothly.
Can anyone advise how I regain the password window?
This only reared its head after the last update.

Does "password number" mean a four-digit PIN?

If so, I don't see how that could affect logging in to websites.

But it's difficult to imagine what happened without exact wording or a screenshot.

Before the last update when the pin window came on the screen I logged on with an 8 number pin. Now the window does not appear. In its place is a message saying 'something happened and the pin is not available'. Below this are 2 further messages, 'reset pin' and 'other login options'. I use the options to login with my ms account password.
I have since gone into settings/accounts/ sign in options and changed my pin, using the original 8 digit pin and created a new pin again with the same 8 digits, hoping it would reset. However, on re boot, the window appears and now asks for my password and logs in with my ms account password.

You don't get Sign-in Options below the password entry box?

Yes I do; selected the pin option and it works after I reinstalled the same pin I've been using for ages.
So, sorted.