I bought a 3 computer 2011 NIS CD but I am unable to install this CD onto a system that had NIS (two days left on former installation). I uninstalled the old version, used the latest Removal-tool but when I install NIS from the just purchased CD I am not prompted for product key and the former version (with two days left) is re-installed. What do I have to do to achieve installation of the new license?