Sometimes when my MBP starts up, I hear a scratchy noise coming from right under the center of a keyboard. Sounds like a mouse is in there digging or clawing frantically on the aluminum. I know its not the HDD, because I've heard the clicking noise that those do when they are about to die. Fan maybe? Does the fan turn on even when the lappy is just turned on? Its coming from under the center of the keyboard. Been doing this for some time now off and on. Anybody run into this before???