I've got a seemingly common "blocked" drive problem where there is a physical blockage of the optical drive preventing discs from being inserted. I've tried disassembling the Macbook and the optical drive and there appears to be a small, for lack of a better term, arm blocking the disc slot. This arm is just sticking up in the way and I really don't see what the point of it is. Is this the problem? How should the internals of the super multi DVD rewriter look?