|The question should be directed to Norton.|
The purchase of the key should have had directions with it.
The file, probably in your Downloads folder on the one machine should be still there and you can just copy it and either email it to yourself or move it with a flash drive to the other machine. I the machines are significantly newer and different operating systems you may want to go with a new download though.
You have to be a little bit crazy to keep you from going insane.