Sure, if you let us know a little about your computer, I cant see it from here

That happened to me once. I did a system restore, and my sound returned. I never did figure out why I lost it.

Its happened to me before too and I have to restart the computer and then the sounds return. Strange isnt it?

Others may have better suggestions.
To update your sound. Windows XP
Start - control panel - open system icon - Hardware Tab - Device manager -
Click the plus sign for sound and video.
Right click your sound (whatever your using) - properties - update drivers -
and follow the directions.
You will need the CD that came with your computer.
See if your sound has been stopped in Services Under
Windows Audio.
Start - Control Panel - Open Administrative Tools - Click Services and Scrowl down the list to
Windows Audio to see if it says - Started. If stopped
Left click Windows Audio and click restart. -
Or
Right click Windows Audio - left click Properties - Left click Start.
While in Services check to see if Plug and Play is Started.

Cboy Thanks, will print your instructions for future use.Sound came back after messing with a few things.Don't know what I did.But it's back.Thankyou again.

You might ought to check your speaker cables for a loose connection.