Hi everyone! On the bottom of my MBA Rev. B, I have no clue how it happened, but I have about 2 missing screws that is causing the casing to pop off. I really need these two screws to secure the bottom of the laptop. If I go to the Genius Bar, do you think they will be able to help me out or how much they may charge? (I don't have a warranty anymore, however). Or, do you any of you have some extra screws lying around? Thank you!