I just had a macbook replaced because of some physical defects. My new one however seems to have a different prob. When i insert a disc there is the "normal" noise accompanied by a series of loud clicks. I can only compare the clicks to the noise you would hear when you overtighten to the point of stripping or when you turn your gas cap too far. Sounds like something in the disc drive isnt aligned properly or is over tight. Anyone else heard of this?