laptops came pre-loaded with Norton Internet Security but I already have an account.

I have a really dumb question - please bear with me !   I have a Norton Internet Security subscription that is currently running on my old desktop.  I have liscence to download to 2 more computers.   I just bought 2 laptops that came pre-loaded with Norton Internet Security.  I have not activated it yet.   What do I do to get MY stuff on my new laptops ?  Do I simply  download from my account and it will overwrite the files that came pre-loaded or do I try to activate what came on my laptops and it will somehow know that I alreday have an account ?