I just bought a refurbished macbook pro and at first the screen wouldn't turn on when I started it up, the little sleep light was on though. I pressed and held down a key for a few seconds right after pressing the power button and the screen worked. My question is, should I be worried about this? I got the computer from a company I later found out is really difficult to deal with so I don't want to have to return or exchange it, but I also want to get my moneys worth. any thoughts?