BeagleBone Black not detected after partion and unplug usb cable

Hi everyone. Can someone help with this problem. Thanks a million in advance.
I bought a new BeagleBone Black. I followed the instruction in the beableboard website to install embedded Ubuntu on it. The first step is using the fdisk on my laptop to partition. After I finished this step, I unplugged the usb cable(without using the safe remove device). From that time, when i try to plug the Board using the usb cable, the LEDs in the board are not lighting anymore, there's no new mounted device infomation on my Ubuntu laptop and the ethernet periodically shows "wired connection disconnected". Please help me make it alive again. Thank you very much.

So... You "re-partitioned" the BeagleBone Black over the usb-otg
cable? While it was plugged into the pc?