Login password after booting the computer

Users questions:My computer does not set any login password, but today suddenly shows what landing after boot password.
Experts answer: is definitely someone to set you up. No other could. The problem now is you do not know the password, right? Teach you about ways to break the boot press F8 and then select "safe mode with command lineType "start after the dos prompt, start typing" netuser user name (that is when you log in, but you do not know the password) 1234 "This password has been changed to 1234, and of course that you can enter other content
  • This information provided by the users.Thanks!