I don't have an answer, but I can verify your issue at least.

I chose to install Vista Beta 2 (clean) on a SN41G2-V3 Shuttle computer with the following components:
FN41 mainboard with a nVidia chipset with nForce2 I believe
CPU is an AM Athlon XP Barton 2800+ (1.24GHz)
Memory is 1GB (2x512MB) Crucial PC2700 running dual channel at 166MHz (very slow, but I assembled this box out of odds and ends in order to more realistically duplicate an average older system)
ASUS n6600 graphics card
Western Digital 80GB SATA HDD
ASUS X-multi CD/DVD RW Drive
The graphics are clean and crisp, my DSL and home network were recognized with a minimum of issues, but the platform refuses to recognize my on-board sound and/or the nForce. It tells me that there are no sound components attached (although I do have an USB powered speaker plugged-in).
When I attempt to load the CD that contains the mainboards drivers it brings up the autoload screen minus any selection (that in itself is a separate issue) and when attempting to load the driver manually it tells me that nForce is not found more than likely because the driver has not been loaded.
Before I attempt to load it on that system can some wonderful person verify IF the Vista nVidia audio drivers listed in this forum work with the Beta 2 version?
Thanks!
EDIT Update: Just stumbled upon the download site that has the Beta 2 drivers for Nvidia nForce. They are one step up from the ones currently listed in the Vista Drivers section of this forum. The URL is: http://www.nzone.com/object/nzone_download..._x86_beta2.html