IDE drive moved between 2 Boxes

Searched the Forum but nothing quite on topic.

40 gig IDE drive with no history of problems.
Used on Box #1 no probs, took to machhine two to test machine #2.
Machine #2 was OK. Moved IDE HDD back to #1 machine cannot boot.
I cleared CMOS, reset Award Bios V1.0A and BIOS recognizes and IDs HDD and CD.

Difficult to get CD to boot too. Says "no emulation when trying to but XP PRO install disk.

Tried to do Repair but it keeps locking me out for wrong password.

The drive/installation does not normally require password.
as user and admin both have install permissions.

Can I coax the BIOS into letting me boot from the IDE drive as it has no problems? CHKDSK say it is ok.

BTW
ASUS MOBO and AMD CPU.

Questions:
I've tried switching the IDE 80 pin cables (they are interchangable and both shielded?)

What setting for BIOS:
"Plug and Play"?
Anything other than Type "AUTO" for Primary Master?

 

The cable should have read 40 pin.