A few days ago I noticed space was missing - a lot (2 GB or so), and thought it was iTunes. Fixed that problem. Now it's worse. Something is wrong that only some of my space is showing up out of what's there (should be 6-7 GB of space available). I only have a 40 GB HDD so it's essential I find this missing free space. What can I do? I am guessing there are duplicates, but where do I begin to look? And what else can I do?