When the battery is fully discharged, USB charging is not possible. Connect the AC power adapter to charge the battery.
If the battery is not fully discharged and does not begin charging when connected to the USB port on the computer, try connecting the Reader to a different port on the computer or to a different computer. If the battery still does not charge, service may be required. The Sony® eService Web site at http://eservice.sony.com/ can assist you in obtaining service from a Sony Service Center or locating a Sony Authorized Servicer.