alsamixer: function snd_ctl_open failed for default: No such file or directory
By the way, I should probably have pointed out that I am running kernel 2.4.27. But I tried rebooting to the old kernel (2.4.22-10mdk which comes with Mandrake 9.2) and got the same result.
I have just discovered that there is no sound coming out of the headphone socket on the front of the laptop (only the internal speakers). So we may be looking at a hardware problem here