On my PowerBook G4, there is a hexagon shaped screw on the left hand side of the screen, close to the bottom which has become loose. This causes the lid to rattle slightly with movement. Can this screw be tightened with a special Allen Hex Key tool? If so, where do I get it? The Genius bar werent very helpful, saying that it would take three hours to dismantle the laptop to get at it (very awkward angle because of the position of the screw). Surely the tool they were referring to could be cut down a bit to fit in-between the lid and the back of the laptop?