The sound wont work on my camera - Olympus Cameras

Most cameras from 2004 did not include sound on the video feature.

What does your user manual say?

From my little research using Yahoo Search, I have found that your camera does have a built-in speaker, but no mention of a microphone

NOTE: Movie and Sound Recording Modes"
The C-770's Movie mode is accessible via the Mode dial on top of the camera (marked with a small movie camera symbol). Once in Movie mode, you can record QuickTime or MPEG4 movies with or without sound.

So there you have it. You have to tell the camera you want it to record sound or not and that is going to be located in the user manual.