My macbook air screengot a sratch or a crack, im not sure. And these Balckish bluish, purplish, fuzzy line are appearing aroung the scratch/crack mark. When i take a screen shot none of the crack/straches appear. Thats why im thinking it might be a problem with the plastic case. Im using the second version of the macbook air i think. The one that came out in 2011. If it a problem with the plastic case, Where could i replace it for a low cost