My asus g751 suddenly shut down.It doesnt work. Neither is it charging.The charging icon doesnt show any light signal. It was

1. Remove charger.
2. Remove battery.
3. Press power button for 20 seconds.
4. Reconnect battery and charger and see if any lights come on and then try powering up the laptop.

or
1. Remove battery.
2. Connect charger
3. Press and hold power button for 20 seconds, then release it may now power up.

 
Seems like something died. I agree with zero. It seems like a battery problem. If you follow the ^^ instructions either the battery will recover or your laptop will work with power straight from the charger. If nothing happens the problem lies elsewhere and ou probably would need to take it to a professional.