Hmm, not that different from mine, except for the soundcard... Ok, have you installed the latest Via 4in1 drivers and IDE tool? Cause if I remember correctly, windows doesen't install the proper AGP drivers for the geforce card. It won't hurt to install them.
But I really think you should get a new soundcard. That one is a wee bit old. They aren't that expensive, and trust me, you'll hear the difference. If you're gonna get one, you have to remember some things. The SB Live! series has some problems with VIA chipset and bios, but if you've flashed it, than no worries, I suggest you check it up anyway. But if you get the SB Audigy (which I have and had no problems with it so far), it ain't that dissimilar, except it won't have any of the major problems as the Live! series had.
Upgrading to XP also solves
of problems, BUT there is one down side. The SB16 emulator will not be supported in it. However, I've found a program that contains it's own emulator, and will work for XP.
Anyway, it could be that the VIA 4in1 drivers aren't installed which might be bugging up the game, or the the soundcard.
Hope some of this helps...
But for any other reason, upgrade you're sound card, you'll hear the difference!