How to add Norton product key to account?

Hello,

I have a Norton 360 key with about 6 months of life still on it. I want to add the key to my account so that I can download Norton 360 from the site to install on another machine as I have lost my disc.

Under my account I can only see past product keys with no way to add an additional one. It seems the key I have was never tied to my email.

How do I add the key? The only box I can find to input a key is only to renew products, not add my existing one.

Thank you,