I was doing a 7-Pass Erase of a hard drive that I had switched out of my MBP. During the process, the USB cable connecting my hard drive to my MBP got disconnected. Now, whenever I connect this external drive to my MBP, it doesn't show up in the desktop or under disk utiltiy. How can I can continue the process of erasing and formatting the drive? What do I have to do in order for OS X to recognize it?