How do I stop a procedure in the middle of the procedure?

And here's the twist:
We're in the ONCLICK even of a form button.
We're used "RETURN" but the form locks up. We read about what RETURN does, and it states that it returns to the calling program/procedure. But what if there was no calling program/procedure?

I'm guessing the problem is based on what we're returning to, which is a user event. We're in the ONCLICK event of a button. So I guess we're trying to return to "...waiting for customer to click button" phase.

Thanks,
Dustin