If the device is plugged in and still is not turning on, it may not actually be charging the battery. First try plugging the device into a different outlet in your home to ensure it is either the device or the charger. If it still not charging, you may have to purchase a new charger. If the device is still not powering on the charging port on the device could be damaged. This will need to be replaced. If nothing else has fixed the issue, the battery is your last option. Replace the battery and the device should work correctly.