"Program event" for Windows is missing - cannot set sound ..

I'm using Windows XP and IE7 on an old Dell D610 laptop. Recently (cannot
pinpoint exactly when it happened) I lost all sounds, except that annoying
default beep. There's no startup sound, no shutdown sound.

When I open Control Panel>Sounds and Audio Devices>Sounds tab in an attempt
reset the sound scheme, I cannot do anything. There is a program event for
Microsoft Office, but that's not my concern. I'm wondering why the program
event for Microsoft *Windows* is not there? There is an icon for the Office
program event -- it's that small white window with a blue title bar at the
top. The same icon appears again, but with no text next to it. I almost think
that this represents the
Microsoft Windows program event, however it's missing! If I click on that
icon, the empty space (where text should be) is "selected" but when I look
down at the Sounds section below, there are no sounds to choose from -- it
says (none) in disabled text.

It's very hard to describe this problem so I hope someone will be able to
understand the issue here. Everywhere I've looked online can only suggest
editing the registry, which is a big and daunting task for a "basic" user
like me.

Help!! Any clues or suggestions??

Thanks!!