MCP51 AC97 on-board sound worked when I installed Ubuntu, then stopped!

[Adam Funk]

On 2006-08-12, Adam Funk <a24061 at yahoo.com> wrote:
...
> The sound worked then.  At some point it stopped working, and now when
> I run XMMS (for example) I get the "Couldn't open audio / Please check
> that: Your soundcard is configured properly..." error.

This is weird.  XMMS and totem won't play sound, but gxine will.  And
the XFCE4 volume control goes back to zero right after I try to turn
it up.