So I have this MBA that I bought from a buddy, he said it had a bad LCD. I ordered a new LCD and still nothing, but it works with an external display. When I boot up I can see very very faint black vertical lines in the background, but that's all I get. Also, if I take this into an Apple store will they diagnose it and give me a quote, since I worked on it on my own? Wasn't sure what their policy is.