This is good info on powerbooks. I have a 150 and soon I'm going to have a 145b and some 100s that I think just need an os. I want to know how hard it is to put a new hard drive into he powerbook 150 because I am getting to the point where I need to start deleting things from it. So can I just format it with one of the programs on the utilities disk or can I format it with transmac from my PC? I just might make a file server out of it for some other macs.