Low quality audio on playback of some files

[Plinko]

I'm attempting to build a Divx box for my home theater. I'm trying to just use the parts in my house, so it won't be a high end machine, but it meets the DivX system requirements.
Certain movies have very poor quality audio on my DivX box running Windows 98 SE. I've tried these movies on my regular PC, and they sound perfect. I've put Windows XP on my DivX box, and the movies sound fine, but I can't use XP since it's a RAM and processor hog, and my videos lag in XP.
I've attempted the Divx 3 and Divx 4 codecs, the Nimo codecs, various players, etc. I've even messed around with the "Set Stereo" options to no avail.
It's probably not my DIvx box hardware, since it played the movies fine in XP, and it plays some Divx movies just fine - all MPEG, and all MP3's are fine too.
It's probably not the movies, because they work fine on every other system.
To get this problem to repeat, I simply format the drive, installed Windows 98 SE typical, install video drivers, install Divx codecs, play movie. Nothing else is installed or removed.
Any suggestions before I do something crazy like install Windows ME on it?

[diji1]

Just a suggestion - run win2K ? It runs a s***load better than XP in terms of resource usage on lower-end machines ..... once again ppl have fallen for the hype regarding a new OS im afraid, i am beginning to beelieve m$ is paying ppl off to say nice things about it...

[Plinko]

That's a possibility. I've put Win 2k on it before, but I don't recall testing Divx on it. I just assumed that Win2k would be as resource hungry and media unfriendly as XP.