It may well be the display only. Try this... Turn it completely off. Attach an external monitor, turn on the external monitor and then turn on the laptop.
Can you see on the external screen?
If you can see on the external monitor, then your attached display or its ribbon cable are your problem.
If you can't see on the external monitor, and you are sure the laptop is on (sounds for fan, hard drive, etc.,) then it is probably your graphics card/GPU that is going to need replacing (and possibly the motherboard).
NOTE: If the laptop is under warranty still, do not open it up or do any work on it. Contact the manufacturer about a repair/replacement.