Bought a MacBook two months ago, and already I'm hearing this white static like noise coming from inside. It won't stop. Also, when I open the laptop, the screen flickers a little bit. I did not buy a warranty, but I think that 90 day warranty is still good. What do I do? Do I call Apple? If so, what is their number? Do I mail back my computer? Will they replace it? Will the same thing happen again? Thank you so much.