WHY can't I disable digital playback?

I have a machine here with a FRESH INSTALL of Win XP SP2 and I can’t get a drive out of digital playback mode. I tried 3 different types of drives and unchecked the “Enable Digital Playback” checkbox in device manager. Regardless of settings, drive continues to operate in digital playback mode even after a reboot. The drive can only be forced into analog playback mode using the front panel button.

Is this something to do with my motherboard or its chipset? The motherboard is an Intel i815 chipset D815EEA2 and it has the latest BIOS.

My other machine with same XP SP2 honors the “Enable Digital Playback” checkbox settings.