Upgrade license for Win8Pro not just Win 8. Can be used on any computer that has XP , Vista , or 7 on it already . OEM license can be used on bare metal . This »www.newegg.com/Product/P ··· bmit=ENE is a good description of the different versions .
question is whether user can move installation to a different PC (and use it solely on moved one). Answer is yes: upgrade is not OEM, but retail version.