Ok, on that note, I might know a bit what happen. Maybe you only have 1 account on your pc or laptop, and that account does not have a password on it, or the password is disable.
First, go to the control panel, then look for something that is user accounts . That where all things that are users start. There, you should see your account. If its what I think it is, your password is deleted, so go do change password and try adding one. I am not entirely sure, but maybe that what it is.