Are you sure the computer is still working though the screen stays blank?
Is it still under warranty?
Try pressing Fn+F4 for several times, see if it makes any difference? This key combination is to switch system display between local LCD and external screen.
> still nothing
Was the computer powered on when pressing the Fn+F4 keys. It might be silly, I just double check hehe. :)
Okay. When did the issue start? Did you try powering off the machine after seeing the blank screen?
If not, please hold the power button for a while util you see the power light is off and make sure the machine is shutdown. Wait for a while, turn it on again.
If still nothing shown on screen during the booting process, it is definitely a hardware issue, you need to bring the laptop to a local repairer for services.
Did the test of powering off and on?