Disable a User Account
You must use an account that is in the Domain Admins group to perform this procedure.
To disable a user account
Click Start, click All Programs, click Windows Essential Business Server, and then click Windows Essential Business Server Administration Console.
Click the Users and Groups tab, and then click User Management.
Click the user account that you want to disable. The Status must be Enabled.
In the tasks pane, click Disable user account.
If you want to reassign the client access license (CAL) that is currently assigned to the user account, in the Disable User Account dialog box, click Release the CAL from this user account.