Digital Sound System 80 & USB

I just upgraded from Win98 to XP Pro on my old generic
400Mhz desktop PC. My Microsoft Digital Sound System 80
ran just fine under Win98 - it gave me digital sound
through the USB port, including access to the equalizer.
However, when I try to install the MS Digital Sound
System 80 software under XP Pro, I get "USB Host
Controller was not found" even though it's shown in the
device manager as working properly, and "Microsoft
Digital Sound System Composite Device" is shown
under "Universal Serial Bus controllers" and is working
properly, and "Microsoft Digital Sound System 80" is
shown under "Sound, video and game controllers" and is
working properly.

I've tried uninstalling the system, starting up the
computer, and plugging it back in. I've tried
uninstalling the USB system and reinstalling it. Nothing
works.

I don't want to have to run this system only through my
sound card - I want my digital sound back. What can I do?

TIA,

Kevin Withers