fedore 11: yum update knocks out audio
 

I did a brand new install of fedora 11 and the sound worked fine. I then did yum update and it downloaded and installed about 440 updates, after which the sound no longer works. I've done this new-install-followed-by-yum-update procedure twice and both times the audio disappears after the updates.
I installed hwbrowser and it showed the sound device present as Via Technolgies Inc VT8233/A/8235/8237, Driver: snd_via82xx. I've been through the settings and checked the volume levels and they're all fine.
is there a way to get the sound back?
do I have to wait for another update to restore the sound?
thanks for any advice.

1 ) fedora has had sound issues since fedora 8 so ...
2) besides a Reinstall , what have you done ??? to try to fix things .
3) it is possible that it is just muted , that that check box is checked .