I have a 15 inch 1.5 ghz powerbook "aluminum". It has two slots, which are each occupied by 256 DDR SDRAM sticks. I bought a 1 gb memory stick which I plan to install in one of the slots to replace the 256. Does it matter which slot (upper or lower) that I install the RAM into? I was thinking of just taking out the 256 in the top slot and replacing it with the 1gb, however I was also thinking of putting the 1gb in the bottom slot so it would be easier if I were to upgrade the other 256 later. My questions are 1. Does it matter which one I replace and which one I keep? and 2. I have never installed RAM before and I was wondering if after I install it and close the powerbook back up, do I just turn it on and it recognizes it? No configuring necessary? Thank you!