I have a 13" Macbook Pro with only 160GB of internal hard-drive space. I have an external hard-drive that backs everything up, but before I work on getting a better hard-drive for inside my MacBook Pro, I want to make sure of a couple things: 1. When I start up my MacBook Pro after the "procedure" it will put everything back to exactly how it is, right? Like, to the point where it doesn't seem like there is a new hard-drive in it? 2. Will my iTunes account remain the exact same? I don't lose all of my music, do I? 3. About how long will it take to reinstall everything?