I'm having sound problems ever since I installed Virtualbox, which persisted
even after I removed it. My on board sound card is just being found. I've
even tried 2 other sound cards and they also are just not detected. I
vaguely remember something about 64 bit during the install and may have
chosen the wrong option then as it's an AMD 64 3000+ CPU.

My lshw shows the sound card as "UNCLAIMED" - what is that all about?

*-multimedia UNCLAIMED
description: Multimedia audio controller
product: IXP SB400 AC'97 Audio Controller
vendor: ATI Technologies Inc
physical id: 14.5
bus info: pci@0000:00:14.5
version: 01
width: 32 bits
clock: 66MHz
capabilities: bus_master cap_list
configuration: latency=64 mingnt=2

I've tried modprobe but it doesn't respond to any names I've tried.

Can you help? When I boot with a live CD it still works. I'm on 8.04 but
will be installing the next version in a week or so when it becomes
available and I'm sure that will fix it as it was working fine before.
That's not the solution I want though. I'd far rather lean what's going on
and how to fix it!

I tried it also, but no help here either. I have almost the same
situation as Leslie, right down to running VirtualBox and an AMD CPU
running 64 bit.

The two differences are that my sound card is not listed as
"UNCLAIMED" in the lshw output, and my sound survived some time after
installing VirtualBox, in fact, it only recently died.

All I hear from the speakers now is a faint clicking. All is well on a
live CD though.

Unclaimed means that the card is detected but no driver is installed which
probably explains why you are having a problem. Virtualbox uses its own drivers
for sound, video and network card.

I would start by going to Hardware drivers in System, Administration and see if
it offers to install the correct driver.

There are no hardware drivers listed in that utility - none install or ready
to be enabled, just an empty box. Virtualbox may have it's own drivers but I
got no sound in it either.