2 WVista sent to recycle. NIS still 100 days reminding. How install NIS on 3 new W8?

I had 2 older W VIsta that I sent to recycle - without thinking to uninstall NIS on them. I still have about 100 days left on my actual NIS subscription. I bought 3 new W8 recently for home family. How can I install my actual reminding subscription of NIS to those 3 new PC?