Hi I have a CanoScan Lide 30 which has been fine in the past. As soon as you plug it into a USB drive, it starts up and gets ready to scan. When I plug it into my current-generation iMac, it does nothing. As if it's completely dead or there's no power source. I tried it on my MacBook Pro, too, and it did the same thing - nothing. But then I plug it into my dad's PC and it works perfectly fine. ...Help?