Hi, I have an 80Gb iPod. Recently it has started acting strangely - turning itself on and off constantly. I have tried restoring it (putting it in disk mode/using iTunes 'restore') - but when I do that I get an error message saying 'could not restore iPod because could not unmount iPod'. I have tried formatting the iPod using 'Disk Utility' and it says 'can not unmount' also. Does anybody know what I can do?!?