Try unpluging your laptop charger from the wall (but leave it in your laptop) and hold the on button on your laptopn untill the light on the charger goes off. this should drian all power from your battery and the charger, once the light on the charger has gone off plug it back in again, wait for 60 at least seconds and try turning your laptopn on.
actually it shoulb be remove the battery and the power plug ,hold in the power button to for 60sec drian all power from the motherboards capasitors ,and then connect it back up and try agian ,that the way it works in my neck of the woods anyway