What? No, that wouldn't make Windows a derivative work. We're talking about derivative works here. The 'reddit thread' I linked to isn't important; the point was that someone made artwork based on a TV show, and had that artwork turned into a Tshirt that is now selling at Hot Topic by the creators of that TV show, without having any choice in the matter. In other words, they have no claim to their artwork because it is a derivative work.