SOFT RESET:
While on the charger:
Hold the LAP and MODE buttons for 5 seconds
The 'Charging' display should appear in 5-15 seconds

If the display Takes 10+ seconds to return you need to do a Hard Reset

HARD RESET - Device will be back to default settings - ALL DATA GONE!
While OFF the charger:
Device power OFF
Hold the MODE and PWR buttons untill the device turn on
Down arrow to select YES
ENTER

The device will reboot and turn back on