No Sound in Ubuntu 10.04

[Rob]

Has anyone else had problems with sound in 10.04?  I have two desktops
here (the one I'm using now) and another one in another room.  I have
10.04 installed on this machine and the sound works fine.  It is a
Lenovo A61 Tower w/AMD 64x2 processor.

My other desktop is an Alienware w/500 gig HD and 2 Gig RAM.  I have
tried everything I can think of to get sound working including calling
up the Alsa Mixer in a terminal (the Master is always muted which I then
unmute and increase the volume with no effect).  I have a SB Audigy 2 ZS
soundcard with Via 8237 chipset.

I know it's not a hardware problem because sound worked fine with prior
versions of Ubuntu (and with a recent version of Dream Linux both from
the live CD and, as installed to hard drive).

If anyone has had similar problems and solved it, I'd sure love to hear
the fix!

Many thanks,
Rob