Since I upgraded to 9.04, that has happened to me several times. Each
time it turned out that the PCM level on the volume control panel
somehow got turned down. To access this, right click on the little
speaker icon and select "Open Volume Control".

Did you install the restricted CODECS? Did you have a sound card or built in
sound device?

This thread "sound" needs to get on its OWN thread.

Hijacking a thread - meaning, clicking reply to one thread and adding someone
totally new to it - is just wrong.