Cannot access CD-ROM drive on old NetVista

HI --

I'm trying to install Windows XP on an old NetVista PC for a project I'm
working on. But I cannot get the CD-ROM drive to work.

The BIOS recognizes the CD-ROM.

The CD-ROM is the second boot device in the boot order sequence, after the
floppy drive.

IBM's diagnostics and my PC-Doctor (both run off of bootable floppies) have
run and passed over a dozen tests on the CD-ROM. I have watched and heard
the drive as the diagnostic programs seeked, re-seeked, read, etc. I have
seen the diagnostic programs open and close the drive.

I have done all this with three different CD-ROM drives and two different
IDE cables. All the drives have passed.

However, when I try to boot from the Windows XP install disk, the PC doesn't
detect the CD. It finds no floppy to boot from, apparently misses the CD
altogether, finds nothing to boot off of on the hard drive, and stops with a
boot error.

I have tried booting from the Windows XP install CD and two other bootable
CDs. The PC never boots from them.

I then tried installing Windows XP using the six floppy disks. As soon as
the Setup finished loading Disk 6, it announced that it couldn't find a
CD-ROM drive and aborted.

The drive is there. It has power. The BIOS sees it. The diagnostic programs
see it. What is happening here?

Thanks,
CL