I think Dai; nailed your problem!
anytime you add an IDE to a system with Sata drives and No IDE drives, the addition of the IDE drive makes the bios alter the boot priority for your hard drive on its own
so to adjust this problem after you add the IDE drive; you must enter the bios and set the sata drive to boot as second option / the cd-rom is normally set to first boot.
dont forget to save the bios changes / then exit
keep us posted with your progress
