I'm on a macbook pro unibody late 2008. Today, I just got my hand on the seagate momentus XT 750 GB. I want to clone whatever I have in my current hard drive to the XT, except for the download folders, which weigh in at 460 GB. Then, I would want to delete everything else except for the download folder, off from my old disk, in order to use it as an external storage. If I were to do this, would it render my files in the download folder inaccessible or corrupted? Or is there other better way of uninstalling OSX off from my old disk?