How do I get back into Windows? I am stuck on a page asking for a "challenge question" and I don't know what that is or how to get unstuck and back Windows. It asks to fill in something with the example 'A1b2C3' . This is an issue with Windows 11. I am typing now on my Windows 10 laptop. I tried doing a safe boot up but cannot get rid of the 'challenge phrase' screen to do anything else at all except shut down. Every time, it boots up to show the same. It would not accept my fingerprint, password or PIN prior to the lock down. Too many invalid attempts at signing in is the message on the screen.