I have a question of (loaded) hard drive compatibility between systems. Here is what I'm trying to do. I just bought a 15" powerbook g4 with an 80gb HD and I'm upgrading it to 320gb. I ALSO have a 12" powerbook g4 with a crashed hard drive. Am I able to simply put the 80gb 15" HD into the 12" and have the system run? or is the OS loaded according to the computer's specifications? In other words, will I have to reinstall the system once the old hard drive is put in the 12" PB? thanks!