There're many forum out there discuss about this topic "my laptop screen turned black even though the laptop is still running."
Turns out it has something to do with excessive charge stored within the components of the laptop. In this situation there is a failsafe that will stop current going to different parts and because our laptop screen uses more power than anything, so it is most often affected.
Here's what you can do before you take your laptop to the repair shop or any centre.
1) Unplug the power, take out your laptop battery, and
2) Hold down the power button for around 60seconds.
*** This will release any excess charge built up in the machine. ***
3) Plug your charger back to your laptop and try to turn it on.
If the above solution doesn't work for you, maybe you have different issues with your screen. Most screen issue else than the topic above will not allow your laptop to boot with all lights on and all the little 'plink' noises.
*** If your laptop have a shortcut eg : Fn + F7 like in ASUS K50IN (F7 = blue rectangle box with X in the middle), make sure you didn't accidentally press it because if you do, then the screen will turn black ***