Strange thing happened. I had been using Rythmbox quite happily and now the sound has gone completely despite making sure pc speaker, headphone and master sound are not muted.

My system is a dual boot XP/Ununtu. If I increase the volume on XP the Ubuntu start up noise gets louder, so maybe this is controlled by XP. There is the Ubuntu start up tune when I boot, but I can't get the radio sound or play disks in rythmbox.

This is some info from the terminal relating to the audio controller:

[SIZE="1"]00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 03)
Subsystem: Toshiba America Info Systems Unknown device ff31
Flags: bus master, medium devsel, latency 0, IRQ 11
I/O ports at 1c00 [size=256]
I/O ports at 1880 [size=64]
Memory at e0100c00 (32-bit, non-prefetchable) [size=512]
Memory at e0100800 (32-bit, non-prefetchable) [size=256]
Capabilities: <access denied>[SIZE="1"]

Any ideas?

Here's a first. I'll answer my own question...

There are two volume controls - one for the Ubuntu o/s and the other for Rythmbox.

If one is muted, guess what happens. Nothing!!!

Hello,

one time I had a notebook with dual-boot. When I booted to Linux, everything worked well. When I then restarted (soft-restart) to Windows, still everything worked well. But when I (soft-)restarted from Windows to Linux, graphics was badly broken. Apparently, not everything was reset during the reboot. I had to turn the computer off/on and only then boot to Linux to make it working properly. Might this be your problem?

If my understanding of your post is correct, I'm not sure that I do this. I try to be disciplined about shutting down windows and linux first and not leaving things on reboot.

At the moment everything's working well, so whilst I try to understand what's going on, I think the issue was basically two volume controls on Ubuntu, one which was muted and the other which wasn't.

If there's a connection between xp sound and ubuntu sound, that's resolved for now by making sure xp sound is on.