Just an idea, maybe when you installed the nvidia drivers, it knocked the soundcard entry out of /etc/modules.conf ?
I have seen it happen before... if so, all you have to do is put it back in
something like :
alias sound-slot-0 cmpci
post-install sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -L >/dev/null 2>&1 || :
pre-remove sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -S >/dev/null 2>&1 || :
Hope this helps
jimbob