Good afternoon! I've a Macbook Pro Core Duo 1.83ghz. It came with 512mb, i bought 1gb and now i bought 2gb (memory of course). Anyway, now i'm trying to use 2gb memory with 1gb memory so i can get 3gb! Well, when i try this and turn on the computer it just appears me the black screen as it doesnt turn on and the sleep light doing the fade like it was sleeping, but doesn't initiate the OS. Anyone know how i can solve this problem?