Plug the phone without a battery in it into a computer and see if it turns on. if so you have a bad battery, if the capacitive buttons light up but the screen does not then the connector from motherboard to screen has come loose. if nothing lights up at all then you have something else loose. back cover off and check all ribbon connections. if it was a simple fall that did not break the glass then it's likely a connector.
If your just going to trash the damn thing send it to me, i can fix it and put it to use as a test bed for cooking roms.