norton 2011 anti virus

i have norton 2010 on my computer from which i downloaded from your site i only have 3 days left. so i purchased new a copy of norton 2011 anti virus from the store for up to 3 computers. i have 2 computers on my home network i installed it on the other computer ok but i can not install on this computer. norton comes up and shows i only have 3 days left. so please help