If that doesn't work, expand the domain(s) or Workgroups under Microsoft Windows Network so all of the computers appear. Then right-click on the domain name, and  choose "Unmanage Selected." This will remove all the licenses from the computers in that domain. Alternately, you could highlight your domain name under Active Directory, and again right-click and unmanage the computers. Then go to the menu item Network|Enumerate. This will "refresh" the list of computers that can be managed. You can then multi-select the computers you wish to manage and right-click to choose "Manage Selected."