To change your local user account password, head into Settings > Accounts > Sign-In Options > Password, click "Change," enter ...

A good password or a PIN is often difficult ... 4] Enter your new PIN two times. Done! You have successfully reset your Windows login PIN; you can use this new one when logging in to your device.

Add and then remove the PIN Uninstall the Windows Update Perform System ... and see if you can input your password and login successfully. You may also try to add and then remove the PIN.