I'm new to this. I got my beaglebone in the mail last week - 2012-06-06. It had some issues booting every now and then - both using the usb or 5V adapter. I eventually updated the firmware to the latest to see if it would help. For the next few boots, it was reliable. I was able to run opkg to update packages, ssh to it, and mount through usb. Then it died. The only indicator light that comes on is the power light - this is the case with both USB and 5V adapter. I've tried resetting it, mounting it, running the screen command on my laptop to /dev/tty.usbserial*, and nothing.
The only thing I CAN do is mount the flash drive directly on my laptop to overwrite the image, which i've done a few times to see if maybe the image i was loading was corrupt. Nothing seems to help..