I have a couple of clients who can’t have audio in their courses, and one thing I’ve done that has worked well is similar to what Steve mentions – I use characters who kind of drive the course. Each character is represented by a photo, and through the course they “say” and “ask” things (in text of course, since there’s no audio!) and the learner responds. In a couple of cases, I set one of the characters as the “expert” so they provided the feedback on the learner’s choices – in other cases, the feedback just appeared with out a character.
Although I know this can be done in QuizMaker, I’m more comfortable working in straight PowerPoint, so I’ve done this using just Presenter with hyperlinks and animations. Like Blair, I think it works better with the player controls disabled…