I just bought a 13" MBP, upgraded the HDD and the RAM and everything seems to be working fine except the sound. I can hear the chime just fine when the computer turns on, but when I got to turn the volume up or down, it shows that it is up all the way and has a little "not available" symbol (circle with line through it like a no-smoking sign) and won't let me do anything to the sound. Also, where the sound should be showing in the menu bar, there is nothing. What did I do wrong??? help please!