Can you send in a Customer Support ticket specifying which 2 computers had LR installed (please specify the computer name/ID of each computer, and which computer installed LR first, and which one second), and tell us clearly which computer is no longer using LR and should be deactivated.
Please also quote your order number if you have it, or otherwise make sure you are using the same email that you used when purchasing LR when you send in the ticket.
You can send in a ticket here:
http://www.brillkids.com/support/contactus.php