Sean's question asks if computers can create music, and I think that's complicated because, like he said, computers only put out the programs that humans have entered. The physical computer, that box sitting on the floor, obviously can't create anything but a surface for a modem and dust, but if you think of a computer as a human composer's tool and instrument, then maybe. How is programming the computer to make sounds any fundamentally different than plucking out those sounds on a keyboard? Obviously, the sound quality, and aesthetic quality will be different, but is that enough to discount the computer's sounds as music?
If the person programs the computer to make music, it's making music, as an instrument, but not as a creative being unto itself. But as an object, a computer cannot create music, any more than a rock can.