Well I have got absolutely no responses on this problem. He took the Sony DVD Rom back and exchanged it for a Pioneer DVD Rom.
But he gets the same thing. No boot with the Pioneer DVD Rom in. Good boot without the Pioneer DVD Rom. I went to his house to see if I could solve this. I noticed that the Pioneer needed an 80 conductor cable (not 40). I happened to have one with me which I tried but still got the same problem. Reinstalled the CD Rom and everything works fine, (whether it's on the 40 conductor or 80 conductor cable).
He has 2 hard drives (master and slave on an 80 conductor cable).
Why won't this computer accept a DVD Rom when a CD Rom works fine?