Mute Button (touchpad)

Question

why cant i hear any sound or music and the mute button (touchpad) is always orange instead of white like every other button, when i click the mute button , the computer mutes everything but when i click it again it says there is sound but i cant hear it, went to control panel and did not work check the sound icon and said it was ok. what else can i try, its a HP PAVILION DV5