Maybe so, I have the same problem with a Machspeed msnv-939
mainboard with AMD 3800+ dual core processor, which also uses
AC 97 sound drivers.
I was running a dual boot install of XP pro on drive C:
and Vista Ultimate on drive D:
as a work around until (win32 Fujacks) toasted my XP install
but strange enough did nothing to the Vista install.
So I guess I will be stuck without sound until someone
makes a proper set of AC 97 sound drivers for Vista
or until I can afford a Creative sound card with 64 bit
drivers out of box. (I don't like downloading replacement
drivers off the internet, there is no way to know if it's
prepacked with malware.)