Install on new second computer

I'm sure this is a simple question .

 

Last computer purchased in Dec 2006 w/trial version of Norton Internet Security and Antivirus (2007?) running in XP.  Subscribed, renewed and updated each year (up to 3 computers).  Now my computer is "under repair" (so sad) and we are adding a new second computer to the house while we await our trusty old friend.

 

How do I download my software to the new (second) compurter since I did not purchase a CD in a store?  I have my product code and key.  Also, any concerns in the Windows 7 environment to be aware of as I do this?

 

Thank you for your assistance.