Please follow these instructions:
- Disconnect the power from the Motorola modem.
- Disconnect the power from the VBox.
- Power up the Motorola modem.
- Wait a minute or so and then power up the VBox.
See if the VBox connects to the internet automatically. Sometimes the Motorola modem is stuck to the first MAC address it configured itself to. You can restart or reset the modem via its interface: