Today I started it up only to find it hanging at the grey apple screen, waited 5 minutes then finally got into osx where then I couldn't control anything. I could move the mouse around the screen but it was useless I couldn't click or close windows. Just drag the mouse around, does anyone have an idea as to why this is happening? The only thing I can do is put it to sleep by pushing the power button or completely shut it off by holding it.