The Compaq iPAQ Pocket PC 3830. It measures 8.1 cm by 13.3 cm. It was introduced by Compaq in April of 2000. iPAQ was borrowed from Compaq's earlier iPAQ Desktop Personal Computers. The device used a Windows Mobile interface.
Your battery is probably dead. Try charging your device for 12 hours to make sure the battery is fully charged. Make sure you plug in your device to a working power outlet.