If all of the LEDs are dim, that is due to a low voltage battery, or an old worn battery. The best course of action for that is to place the flashlight in a window and let it charge, then try testing again. If the LEDs are still dim, I recommend replacing the battery with a new rechargeable battery. If not all of the LEDs are dim, or the above solutions do not work for your device, check the Nokero N400 Troubleshooting page.
There are a couple reasons for why the flashlight won't turn on, the most common reason, is the device isn't charged. Try placing the flashlight in the sun for a couple hours and try using the device again. If there is still no charge, try putting in a fresh battery. If none of these options work, check out the Nokero N400 Troubleshooting page.