Maybe the message you saw is related to this:
Secure Boot requires a graphics card with a signed option ROM - we can't launch the opROM if the code is unsigned (security hole).
@rbmorse Legacy BIOS mode is not the only option, he can use UEFI Boot but he must have Legacy Boot enabled as well, for the graphics card to work. But the best is to continue using IGP to boot Windows 8 and use ATI for games. 