Amazon is really great when working with customers. However on some thing like this IDK what they will do. This is really a bummer, I don't understand how this is not getting fixed a.s.a.p. I just purchased a 2nd copy from Steam and I can't use it because the machine is running Win8.1. I will try some recommended fixes from support later today but if that doesn't help it will be a problem I may need dive into further. So sad, such a GREAT game and this issue comes up. Seriously people, plan ahead.