Hi,
First, do a hard reset with the laptop. Remove the battery and the charger the press and hold the power button for around 20 secs. If that doesn't do the trick, try plugging in an external monitor and see if you'll get any display. If it works with an external monitor it could be your on-board screen which is faulty and if not re-seat the RAM as well to further test if it's the motherboard. Also try powering on the laptop without it's battery.