I still do not understand why you cannot delete the new user you setup with admin rights though.
What mesage do you get when you try and delete that user? (and I am assuming you are trying to delete the user through control panle, user accounts)
It seems that the first user account you create has to have Admin status. You can then create further accounts with Admin or Limited status. If you have more than one user account with admin sttus (not including the actual Administrator account), then you have the option to delete either one. However, once you have only one user account with admin rights the option to delte it is not there, even when logged in as Administrator.