A
Welcome to Android Central! How old is the tablet? Leave it plugged into a wall outlet for at least 4-6 hours, undisturbed, then try powering on again. Press and hold the Power button for at least 20 seconds. If it doesn't work, then the battery may have failed, or perhaps the motherboard. Off-brand tablets like your Emerson are much more likely to have hardware or firmware defects, so this would not be surprising.