Function keys on a laptop?

OK, I have recently acquired an alienware laptop, and it destroys my old acer in every way except 2. 1 is because it can't do 3d but I don't particularly care about that, 2 is because my acer had on board volume control buttons near the keyboard. On my alienware f8 and f9 have icons for increasing and decreasing the sound but they don't do anything when pressed, any ideas on how to enable these functions?