If there are any lights, or any internal sounds, it is possible that it is actually on, just the display is having a problem.
Turn the laptop off (not sleep or hibernate but off).
Connect an external monitor to the laptop.
Turn on the external monitor.
Turn on the laptop.
NOTE: You may have to press an "external monitor" button. Could be the f4 button or a button with two monitors on it, for the external monitor to work.
If you can see fine on the external monitor, then your attached display, or the ribbon cable that connects it, are your problem.
If you can't see on the external monitor at all, or the problem occurs on the external monitor as well, then it is probably the graphics card/GPU that is the problem, which may require the motherboard be replaced.
You may also want to try hitting CTRL + SHIFT + WIN + B to try and reset your graphics driver as another possible fix.
Did you try connecting an external display to see if you got any signs of life?
If not, or if it didn't show any, then it could be a number of things. Bad battery, motherboard, etc. In that case I would have it looked at. Either by the manufacturer (if under warranty) or a local tech if not.
Mine is working again after being left dormant for several months, but I have no idea what the root cause is. I have suspicions about the cheap aftermarket battery I was using, but I can't provide any logical reason as to how it caused the problem, or how the problem resolved itself. One thing I can say is that the aftermarket battery is going to the recycling centre!