User Accounts

  I was recently trying to set up parental controls on a new user account.  Since a game was saved on the administative account I change the type of account from administative to standard.  Then attempted to make a new account for the administative user.  Anyhow, I messed it up some way and now have no administrative user at all!  I've tryed to change the account type but it prompts for the administative password and instructs you to type in the password and click continue only there is no text box to type into?  Is there any way I can fix this?