Event missing from my Events list - "Default Sound"

I have Windows 98 SE. This week I changed the Startup and Shutdown sounds, and tonight I realized I haven’t been hearing the “ding” sound when I change my volume control. I believe volume control comes under the “Default Sound”. I opened the Sounds list, (in the Control Panel) and “Default Sound” (under Windows) is not even there anymore. I figured I must have done something by mistake, so I went back to all the original sounds and rebooted, but no luck. Since the entry doesn’t exist on the list I can’t associate any sound at all with it. If I go to another user’s screen, I do see Default Sound in the Events list, it’s just not there on the list on my screen. Does anyone know how to restore this?