Sounds like it could be a power delivery failure. If there is no power going to the battery or system itself, there will be no charging or lights turning on. The only other troubleshooting I could recommend would be removing the device from the charger, removing the battery, and holding the power button for 30 seconds while unplugged from both battery power and outlet charger power. Then, reconnect the charger (with battery still removed) and try again. If it works and boots up, then shut it down and reconnect the battery, and try again.
Good luck!