Silent sound setting?

[mjmoody]

I have a MacBook Pro at home, and I was recently allowed to get one for school. I noticed with my new school Mac when I entered notes with Finale I wouldn't "hear" them. When I would playback anything I had written I would hear everything fine, but when I would enter the notes there was no sound. I thought this was something with my Finale settings - but then I tried using Digital Performer. Sure enough, if I tried to enter notes with the pencil tool, or drag notes around, I couldn't hear anything. DP plays back everything fine - but I can't hear anything when entering notes (with the pencil tool) or dragging them around.

So, I'm thinking this is some setting on the computer, but I can't find what it is. It is actually kind of intriguing. I kind of like the setting - it presents a situation where you're composing "away from the piano". I think there are lots of tricks a composer can use when not "inhibited" by what he hears - and this provides a way of entering notes without hearing them - however, I would like to be able to have the option of hearing my notes when entering or moving them. Does anyone know what this setting is??

Thanks! John