PJC1966

My computer has automatically created a login (User) as I didn't have to login before. Each time my computer boots it gives me the window login screen. If I click the (User) Icon it goes to login the automatically logs of again back to the same window. I've tried, F8 (All types of boots), Ctrl+Alt+Del x 2, Guest login, nothing seems to work. Any suggestions to overide or delete the login process that has been created. Thanks, Peter.