The version for the Mac doesn't quit when you ask it to. You have to use
Command-Option-Escape (the general keystroke to abort the frontmost app) to
get rid of it. I also discovered that once you saved the output, it's
permanently stuck and never does any more calculations, which may be the
other thing you saw.
You're question wasn't such a dumb question. Dumb questions are really
hard to come up with. I know professor who used to start off the first
class each term by offering an A to anyone who could ask a really dumb
question. I don't think he ever paid off, but he got some interesting
questions.
Mike Alexander Internet: mta@umich.edu
+1-313-663-1759 Fax: +1-313-327-0567