I just received my new 15" Powerbook. The only problem I have is that none of my 3 USB 2.0 external harddrives work with it. I have used them on other macs and they work just fine. What can the problem be? If I start the disk utility while one is plugged in, it will just freeze up. I'm using a USB mouse, and I used my sony camera on USB, and that worked fine. I'm praying it's not a hardware issue. I loaded all the software updates, but it didn't change anything. What should I do??? Thanks!