A1278 13.3" MBP
Guys, there ISN'T a door on the back giving access to the battery (don't remove) and the HD for the 13.3" model. You make no mention of this issue nor any acknowledgement that the 13" is different. You have to remove 4 screws from the upper part of the bottom, 2 more from the middle sides and three long and one short screw from the very back near the vents, At that point you can lift the bottom case completely off giving you access the the hard drive. You take off the upper bracing and its two build in screws (torx #6, but don't separate the screws from the bracket, then two screws from the bottom retainer, pull up on the clear tag, and the HD is loose, then carefully pull away the ribbon connector. You then remove the (think of Frankensteins bolts coming out of his neck) bolts Torx #6, from the corners. Place the bolts into the corners of the new drive, switch the ribbon cable you took off the old drive, fit the bottom bolts into their holes, add the two screws on the bottom. The "botls" set first into the bottom square holes with copper connectors, then on the upper part they sit in a "half moon" shape cup where the retainer was, when you add the retainer with its opposite half moon copper hole you complete the "frame" holding the HD. Replace the entire bottom case and your ready to format and transfer info from the old drive to the new.