I'd think the best way to make music, for someone who doesn't play an instrument, might be for them to sing a tune into a microphone, and you shopw them how to get the notes into the computer, and use a midi keyboard to see what it sounds like with different instruments playing it. And you could play around with changing the particular notes and seeing what difference that made.

My impression is that a lot of music programs on PCs seem to look at music the opposite way round from me - they talk about setting up a basic rythym first and I reckon that's the last thing that gets settled. But maybe that's just me.

Teaching "Music on the PC" could mean all kinds of things - you might be trying to teach musical theory of some kind (which I've never got my head round), or it could be more about the way people can use the computer techology to get the music that's within them (whether they play an instrument or not)into the computer, and making it sound like something they are proud of, and how to send it to their cousins in Australia on the Internet.