Product Key Reuse with replacement Hard Disk?

I have Office Mac 2011 Family Pak (3 licenses).  It is already installed on an iMan desktop.  It was also installed on an Airbook laptop.  I recently replaced the hard disk on the laptop and did a recovery from my Apple Time Machine.  Office did not work after recovery and was asking for a product key before I could use word, excel, etc.

I found my old install CD (with product key sticker).  I entered the product key and it was accepted.  Office is now working on the laptop.  

I am curious / worried that I may have "used up" my third license on this new hard disk.  Is there way way I can "deactivate" the old / second license from my dead hard drive?  I would like to have one more license - in case I buy a third mac/ laptop.