I've been using the '30 Day Evaluation Period' for nearly 6 months.. this is my second re-install, and I have every feature Vista Ultimate has to offer.
That won't work because the product keys on those laptops and desktops are OEM.. and, when you try to activate them you'll be forced to do it by phone, which isn't normally a problem, but the product activation code (not the key, but the code provided for phone activation) provided to you by your copy of Vista won't match the one Microsuck has in their system. They might ask you a few questions, such as 'has this been installed on another machine' or 'is this your first time activating this copy of Vista', and they might even ask you to verify the manufacturer of the computer that key came from.. in the end, you'll be left with a copy of Vista that will turn into a 'reduced functionality' OS after 3 days (that's how many days before Vista OEM tries to auto-activate itself.. and it will fail since it requires phone activation)
Regardless, you're best bet is to hit up newegg for a legit copy of Vista, or run the trial and re-install it every 180 days.. there are hacks available, but they can leave your PC vulnerable to intrusion.
Do you really think you're going to convince someone to switch to another OS by talking to them like they're stupid?
-mak