I updated my ALSA driver on my Fedora Core 5 system this weekend using the PUP updater. Well, since then I have no sound. There is no volume, but it doesn't complain the sound card isn't there...
I checked the Gnome Volume control to see if the update moved it to zero, but it was just where I left it.
I have an AC97 chip.
I have to go to Windows to listen to YouTube now until this is fixed.