Thank you for your comment.
I had to change a BIOS setting to accept RAID arrays. It's working now.
Thank you for your help and everyone else's!
Set the SATA controller (ICH7R) to RAID mode and reboot. Then press Ctrl-I at POST and add the hard disks to a RAID 5. You'll need to load the Intel Matrix RAID drivers from a diskette to install Windows 2003 Server Enterprise.