Window Server Licenses

[pcfixr]

How do I go about permanetly removing old users.
I have a semi high employee turn over and even if I delete a user out of AD and remove all traces of the employee (Email, Documents folders and Everything I can Find) I still have the employee showing up in my Licenses, If I revoke the license I reinstates when I Restart the server.

I have users who were employed for less than a week useing up licenses on my server.

Thanks

Greg