Sometimes my volume up and down buttons don't work anymore but i can still change the volume using the icon at the top. but when this happens, my programs start to lag and i quit them.. but after that, they do not reopen. when i try restarting from the apple icon, it won't let me, it does nothing. so i am forced to restart by holding down the on/off button. after i restart, then everything is fine. can someone tell me how to fix this? and is it bad foro me to restart my computer incorrectly? thanx in advance.