Where these drives connected to the same IDE bus cable? If so, you may wish to open the case. Is this a custom built PC, namebrand, or clone? Can you get into the BIOS? BTW, usually OAM motherboards use off the shelf BIOS. During the initial bootup process the BIOS will report what drives it detects, which include hard drives and ATAPI drives. Does the BIOS see these drives?