I have a late 2008 unibody MacBook. This happened before, and now is doing it again. When I click or even tap to click, my MacBook acts like I am holding the button down. If I click in sons text it just keeps highlighting as I move, if I click the bachround it wants to just keep making a box. The only wY u can get it to stop is to hold down power till it shuts off. Everything else works like normal, but the MacBook acts like I am holding the button down.