It is hard to know where to begin troubleshooting without more information. Can you tell me more about what you are trying to do and what you mean when you say it did not work? What kind of batteries are you using (NiMH or Alkaline)? Did you measure the voltage to make sure they are charged? What happens when you turn it on? Do you see any signs of life (LEDs, buzzer sounds, LCD, motor movement)? Also, what program is on the 3pi and are you able to program it?