If you install Windows NT on a multiprocessor MB with only one processor installed, you may receive:
HAL: Bad APIC version. HAL: This HAL.DLL requires an MPS version 1.1 system. Replace HAL.DLL which the correct HAL for this system. The system is halting.
This is generally caused by using hardware not on the HCL. Try doing a custom install and if the computer is identified as an MPS machine, change it to AT Compatible.
You could also edit the TXTSETUP.SIF file on the setup diskette and change the \[HAL\] section that reads
mps11_mp = halmps.dll ,2,hal.dll
mps11_mp = hal.dll ,2,hal.dll
When you add the second processor, undo the above change and see tip 466.