i think it is a problem under the button!
try too get the button out of the keyboard if you now
what i meen i think you have pressed it too many times or
too hard that something have come loose if you know what
i meen! if you don´t want too do it your self go too a
computer store and see if they can help you!
sorry 4 my bay english, i´m not that good at it!=)