Leave it off with the charger plugged in for 24 hours. Post again if it doesn't charge up after that.
Is the outlet the charger is plugged into working? That's a common problem.
Look into the charger port with a strong light and a magnifying glass. Is the bar in the center centered, or is it leaning to one side?
Does the charger charge another tablet or phone? If not, the charger could be bad.