Free upgrade on existing nis 2011 says my product key has run out of uses

The notice came up today for my free update to nis 2011, so i clicked on it.  after the update the program tells me that i have had too many installations on my product key.  I only have two computers, one of which doesnt work anymore, and never did a third install, other than this update (which i assume that norton is mistakenly counting as an install).  Ive upgraded through the past six or seven years, the last time which I had to contact online chat for help.  My question is:  how do i fix this without having to do anything other than click a couple of buttons?  (which is all i should have to do on a upgrade).  My existing subscription has about two years on it.