Based upon, what discovered by other members of this forum, it is not necessary to up grade on an activated copy of Vista. Merely follow the instructions for a clean (the best and recommened method for upgrade) install. Just be sure, when they ask for your key number during the installation, do not give it. Just leave that information blank and move to the next step of the installation. After you have installed, use it for a while, you have 30 days to activate (you can actually get two more 30 day extensions after that, but that is really not necessary). Once you are sure that you are happy with the OS, activate and then make a system image, and put it away. If you ever have a problem with your OS you can just replace it with your system image and you will have a brand new OS again. I hope you enjoy, I had mine installed for just about a week now and I think it is fab.
PS Yes you will get your own key.