I broke my laptop by banging its keyboard. It now won't start and only shows a black screen. It shows the LED lights that it's connected to the battery adapter and that it's turned on, but won't do anything else. I removed the hard drive and it tested OK in another laptop.
Does it make any beeps when you turn it on? Does an external monitor show anything when connected?
If answers to both of those is no, you probably have a dead mainboard. Very unlikely to be worthwhile to try and fix.