i am currenty replacing my macbooks 80 gb hard drive with a 120 gb. my 80gb has apparently failed so any ways i bought the hard drive that is recommended for it and it appears to be the same as the one im taking out. however when i attach the sliding case and slide it in, it feels like something is jammed on the left side and it wont go all the way in. any suggestions or idea why it wont slide in correctly?