sysprep on windows 8.1

hi all!

I have upgraded /updated (whatever it is!) from windows 8 pro wmc to windows 8.1 pro wmc using store free update.

I though I will sysprep and keep an image; in order to remove the current user profile I went into audit mode and from control panel --> user accounts successfully deleted the user account and files.

then I did a oobe/generalize to and made the install.wim using dism /capture-image.
when I tried the image on the next laptop, after the welcome screen etc I made a new user (in the new laptop); when I check the profiles I find that Adminstrator is shown in the users folder.

I was under impression that when the oobe /generalize sysprep is done under audit mode, the admin account is automatically disabled/deleted. so when I mount the wim file, I find that Adminstrator account is in the Users folder

how to remove the built-in administrator account so that the install.wim is a real installation file.

regards
neelakantan