there are 2 kinds of IDE cables. the one with fatter wires is 40 conductor, it has 40 wires. 80 conductor, 80 wires is the thinner one. if setting both to cable select doesn't work set each as master or slave depending on what location the drive is connected on the IDE cable. which hard disk is the bios refusing to recognise? it may be a bios limitation, you may need to use an IDE card