logging on to Windows Computer

Windows 10 downloaded to computer. Closed down and later in week (today) tried to sign on and a whole new look to log on. My hotmail.com address appeared and asked for password (I am administrator for computer). I typed in what I thought was my password but showed incorrect and was directed to microsoft to reset password. When I put in the hotmail address I get the message that that is not my account. I have never used the hotmail as a logon before. My question is why was this changed? I use a password as administrator of computer when using Windows 7 but it had nothing to do with hotmail address.