Alright, I just upgraded to a new base model MBP- coming from a G4 PB. I ordered 2 x 2 GB Crucial RAM from Newegg to boost my memory. Now, when I install both 2 GB sticks the MBP doesn't boot, just a black screen and some fan activity. I've tried installing each of the 2 GB Crucial sticks separately- same result, black screen, no boot up. Only when I use either 2 GB Crucial stick with one of the 1 GB stock RAM sticks does the MBP boot and then recognizes 3 GB RAM. The Crucial sticks aren't at fault I guess as both work in conjunction with a 1 GB built-in RAM stick. I would rather not want to exchange my MBP as it is flawless in terms of absence of yellow tinting, no screen gap, etc. I've upgraded RAM for various Mac machines a number of times and never had any problems. This one puzzles me. Any help/info is much appreciated. Thanks in advance!