Hi I just bought the new Aluminum Macbook ($1599 version) and I find when I turn my macbook around with the lid closed that something inside is "slightly" shifting. It will do it everytime I turn it in that direction. Should I worry? Apple says to bring it to the Genius Bar which I will but I wanted your opinions on what it could be or if it is a big deal or not. Because if it is, I am just going to ask them to completely replace my MacBook with a new one. I do not want repercussions of any other hardware because of the shifting parts.