Do you know how to re-set Seagate 300 GB External Drive a(http://www.seagate.com/products/retail/external/usbfirewire)? When I was moving and organizing the back up files on Seagate, my Mac started showing the beach ball. So, I unmounted the drive (then I saw the error sign saying I disconnected incorrectly). Since then, I cannot mount this Seagate for any of my Macs. I disconnected the power for a few minutes in hope it will re-set itself; but it does not work.