I recently got a Sprint iPhone 4S and also have recently reinstalled Snow Leopard on my CD MacBook. Since then, my MacBook will freeze all of a sudden. It doesn't seem to be doing it during a back up or sync or anything. At first, I thought it was due to overheating, but it did it once when it was cool. One thing I've noticed is that it doesn't freeze if I don't plug my iPhone into it via USB. I had a feeling this was the problem, so I didn't plug it in, but kept doing the same stuff I'd normally do, for about a week. No issues at all. One day I needed to charge my iPhone and didn't have an outlet, so I used the USB cable, and after about 20 minutes or so it froze. Any thoughts of what's causing this or what I can do to remedy it?