Macbook Pro stuck on password sign in

I can't log on to my 2011 MacBook Pro. It boots up ok with the chime, then goes to the Apple logo screen, then to the "enter password" screen. There I'm completely stuck as can't get past the log in screen showing my picture and it asking me to put in the password.

It " shakes its head " when I input the password. After a few experiences of this I reset the password using Apple ID but it still doesn't recognise the new password. Tried rebooting using Cmd R and also tried Cmd S.

If I reboot with Cmd-R it goes straight to Apple logo page then sign in page and the box for the password fills up with dots as if I were typing in a very long password

Just to make this into an actual answer…

It seems very likely, after your last comment which I edited into the question body for you, that you have a stuck key which is auto-repeating as you are trying to type.

I think you may need a repair shop.