Why can't I turn on the phone

Halo.. my LG optimus p970 is literally dead. I can't switch it on. When I plug it to the charger, I can see the sign that battery is full. But no more. I take the SD card off.. (I don't know why) then I try to turn it on again.. but nope..nothing happened.

I am next to the moron when it comes to repair almost anything.. so please be kind :) any suggestions I shall do.

Regards..

Karin Sabrina

Indonesia