if the cd is on it's own cable, it must be a master to boot from it. also, it must be seen in the bios. most bioses have on the first page the list of detected devices, and most are set to auto. this will not always detect a cd. there is sometimes another page where you are given the option to scan for disks, this one will usually detect the cd and it will magically now appear in the list. once it's there, you can usually then boot from it. good luck!