Computers are funny things! I played around with the jumpers and I have now got a fully working computer with two hard drives. The bit I don't understand is that in order to achieve this I have my "old 40gb hard disk" jumpered as master and my C disk (with XP Home) as slave. The computer boots to XP and the 40GB drive appears as the F drive(apt letter!). I have two CD drives as D & E. Once booted up everything appears as I would expect and I am able to copy to the second hard drive. I assume that since everything works I should leave well alone. Am I correct in thinking this?