gnome-volume-control: Sorry, no mixer elements and/or devices found

hi,
using gnome-2.8,
sound system used to work fine,
but since experienced a hard disk bad blocks problem, 
gnome-volume-control cannot start again,
always popup a dialog says:
  "Sorry, no mixer elements and/or devices found"

doing 
  `cp sound.wav /dev/dsp`
 still cause noise heard as before;

some application can play sound, but cannot play & record at the same time

`cd /dev; ./MAKEDEV audio` just has no effect.

what could be the problem ?