Well, there's a couple of ways. The first, and best, is done when the OS is first installed. When Win2k asks you if any SCSI or third-party drivers should be installed, you hit F5, and choose to load as a Standard PC. But ACPI (or ICPI) has to be disabled in the BIOS, first ... as you already know.
The second is done in the Device Manager. Select the Microsoft ACPI-Compliant System, under System Devices. Choose to update the driver, and select Standard PC. However, when you reboot, you are going to need <b>all</b> of the drivers for your devices at hand ... preferably on a CD.
But I have a question. Very few people really have any kind of problem with ACPI under Win2k. Why do you need to set the system as APM? What's the problem? I recommend that you don't do this, unless absolutely necessary. Don't change to APM, if the perceived problem is just seeing multiple devices sharing an IRQ. That's <i>normal</i> for Win2k.
You should also be aware that you'll lost the ability to shutdown the computer until you enable the Advanced Power Management in the Control Panel. Otherwise, you'll be hard-booting.
AND ... the system is not likely to be nearly as stable under APM, due to the HAL.
If you already know all this, then just take the advice with a grain of salt, or ignore me, please. Your choice!
<GRIN>
See ya ...
Toejam31
<font color=purple>My Rig:</font color=purple> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=6847" target="_new">http://www.anandtech.com/mysystemrig.html?rigid=6847</A>