A. During installation if Advanced Configuration and Power Interface (ACPI) is detected specific changes are made to the configuration in the form of registry entries and system files.
If you then disable ACPI in the BIOS the OS will fail to boot with a BSOD:
0x00000079 (0x00000004, 0x0000AC31, 0x00000000, 0x00000000)
This is because a separate HAL is used for ACPI, non-ACPI systems. If you no longer want ACPI you will need to reinstall Windows 2000.