ASUS pages give only Windows 8 / Windows 8 Pro as operating systems. Since manufacturers usually give, like, "Windows Vista, 7, 8", indicating the possibility for subsequent OSs usable, it may be you have a Windows 8 "only". ???
Like buying a Hummer, 35" tires, and trying to attach Mondeo (my car) tires 16". Won't do?
It might be doable with a BIOS
downdate, but I doubt it. Hardware issue.
Best wishes, m8.