Methinks he should reset the BIOS to factory defaults, alternatively pull the clock battery out, count to 10, then put it back in.
If I recall correctly, hardware of that vintage needed the master/slave disks correctly matched in the BIOS for them to work. I suspect master is now slave and/or vicey-versa.
Anyways, I'm currently in Uplinkers bad books at the moment (hehe), so perhaps someone else on here could back me up.