I've got 64-bit Vista on my computer, and certain games aren't compatible with it (like FarCry, among others). According to Microsoft's website, Doom 3 isn't compatible with Vista 64, so I was wondering if downloading it via Steam was any different? I got Psychonauts off Steam and there are no compatibility issues, so I was wondering if anyone with 64-bit Vista bought Doom 3 from Steam, and if it worked ok.