I have two IDE channels, two hard disks, a cdrom drive and a dvdrom drive.
The two hard disks occupy a channel, one a master and the other a slave. They work fine.
But when I put the cdrom and dvdrom drives on the other channel, with one master and one slave, the BIOS cannot detect them. I've also tried having them both master, or having them both slave. Or using each one individually as a master, or each one individually as a slave. The BIOS just can't see them!
The drives both work if I plug them in as slaves on the channel with my master HDD.

Ideas as to how I may get the bios to recognise them? It's set to Auto detect the secondary master and the secondary slave.

I've also just tried setting all four drives to cable select, no luck. The computer can still only see the two hard disks.