Before installing memory please check to see that the memory you purchased is correct. Too many people assume that they have purchased the correct RAM only to find that their computer will no longer boot. Be sure to check the size (how many GB) speed  (1067 MHz) and type (DDR3) all of this can effect your computer. Just because it fits in the slot does not mean it is correct. All the information you need for your mac can be found under the apple in about this Mac.