NEW MBA - USED MIGRATION ASSISTANT

[lipskidder]

Hi I got a new MBA. I transferred the files from a previous MBA and selected the files as well as the User name. Now I am trying to create a new admin User Name but this former mac is taking over the User and Groups section. The "Account name" is grayed out and I cannot remove it even though everything else looks fine for the new Admin User Name I made. In Finder under Users I still see the older name even though I deleted it before. Somewhere I read it says it may still be connected to the older mac but I made sure that older mac had migration quit. How can I remover the older User name so that everything in Users and Groups reflect my only acct that I want to use? And why does the "group" say wheel?