Hi @mohammadzuraiqi
With the monitor turned on and connected to a PC that is turned on etc try shining a flashlight at an angle close to the screen and check if you can see any images at all on the screen.
They will be very faint if they are there so trying this in a darkened room may help to see them if they're there.
If they are there, then there's a backlight problem with the screen.
You may have to open the monitor and check the boards and connections etc for any obvious damage. There are 3 boards that could affect the power to the backlight LEDs. The LED driver board ( 04020-02730200), the LED light board (Asus p/n 04020-02730100) and less likely the mainboard (Asus p/n04020-02730400)
Given that the monitor turns on and communicates OK with the PC the mainboard is mostly working OK.
As Asus usually doesn't provide service manuals, post some close up images of the boards in your question. Here's how to do this on ifixit [guide|21499]