ADMINISTRATOR is unable to login

I have a  Dell Inspiron which is not letting me logon. At first I thought it was not recognising the password but when I entered it incorrectly, it prompted me saying that it is incorrect and I also managed to enter with this password in safe mode. I removed the password. However the problem is still on. It says user profile is unable to log on and does not go any further than this. With safe mode I cannot do a back up or do a new user profile.