O cannot start with the Beaglebone

I just bought a BBBW at Arrow Store and I tried to follow the quick start guide, but after boot up the Beaglebone's user LEDs always turn off and I can no longer access to the "kind of Beaglebone storage" from the PC. The power LED stills on and the network connection never done. I don't know if it's a user error or my BBBW is broken. Please help me.