If volume control in tray doesn't give sound and default sound (Ding)
in control panel sounds is missing, add keys to registry.
First use Regedit to search for say toot.wav or some other working sound.

HKCU,AppEvents,Schemes,Apps,.Default
 add another key .Default so it reads
HKCU,AppEvents,Schemes,Apps,.Default,.Default

 Then you can use control panel sounds to set wave file (Ding).
Can also  add two keys to that .Current and .Default
 i.e., there are three .Default keys