Hello,
Thanks you for your fast answer ! I have some others question : What is the definition of principal machine ? The first one I installed the OS and who got online ? Or the one I decide ?
Im new to Linux, I had problem in installing it into a brand new hard drive. So i followed this tutorial :
https://www.youtube.com/watch?v=kHt3jij63o4 . The tutorial explain how to install Zorin in dual boot with windows 8. I don't dual boot, the hard drive is new, there is only ZORIN OS. But I had problem like "grub failed to install". With that tutorial all worked good.
I say that to warn you how I installed Zorin, because I didn't had to enter any key when I installed the OS and even when I got online with it.
So do I need to enter the key I received on my email somewhere on the computer to make it "the principal" ? (windows old habits sorry for newbism :p).
EDIT : and is my Zorin os installation is good (according to the youtube video ?)