I have never come across this issue before. I have a computer with a slave drive. The Master 40gb and the slave is 40gb. Everything was working fine until one day the computer stops recognizing the slave drive. Nothing has changed in any settings. The bios does not see the drive and of course neither does the OS. But I can feel that the hard drive is on when my hand is place on the drive. The computer is a Compaq Presarios 6000 that has had it’s motherboard replaced last year. The OS is Windows XP but at this point, software seems irrelevant. Any ideas?