I have a black macbook. My computer wouldn't turn on, so I plugged it in and turned it on. I noticed that it said "Not Charging". I figured it would go away and start charging. I closed the computer and came back an hour later, and the light on the charger was still green and not amber. Why will my computer only turn on when plugged directly in, and why won't my battery charge? Do I need to get a new charger or a new battery, or is there something else I can do to fix this?