Hi,
Here are some steps that might help you.
1. Hard Reset
- Remove the battery and AC adapter off then press and hold the power button for around 20 secs.
- Put everything back together then turn it back on and see if it will
2. Re-seat the RAM
- Remove the battery and AC adapter first
- Remove the all the RAM off
- After couple of seconds put it back on and try to if the laptop will power on.
3. External Monitor
- See if there's an available monitor
- Hook it up in the laptop and see if you'll see any display from it
- If you'll see a display it means that your built in screen was faulty.