Try the following and see if it will turn on...
1. Unplug your charger cord.
2. Remove the battery.
3. Press and hold the "Power" button for 30 seconds.
4. Now plug back in the power/charger cord. (If it didn't turn on without the cord in, it should turn on once you it is in. Yes sometimes they will turn on, or try to turn on, even with nothing attached/plugged in.)
5. Now put the battery back in.
If this doesn't help, then test the power cord to see if it is good. Either try your cord in another device, or try another devices cord in your laptop.
Should that not be the problem, then check the battery to see if it needs replacing.
Now if it is actually turning on (sound heard from hard drive, fan(s), etc.,) but just nothing on the screen, try this...
1. Turn the laptop off (not sleep or hibernate but off).
2. Connect an external monitor to the laptop.
3. Turn on the external monitor.
4. 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.