OS XP

I am working on a PC with two hard drives one SATA one IDE

The IDE is set as the C drive and SATA as D.

I am trying to make the SATA drive the C drive but if I disconnect either drive the PC fails to boot.

If I disconnect the SATA D drive I get the message:-

Windows could not start because of a computer disk hardware configuration problem.
Could not read from the selected boot disk. Check boot pathway and disk hardware.


If I disconnect the IDE C drive I get the message:-

Disk boot failure, insert system disk and press enter.

That I can understand but not sure how to deal with the first scenario. Have looked in the BIOS but cannot see a setting that needs changing that is immediately apparent.

As always any help and advice gratefully received.

TP