It is common for the monitor backlight to fail, characterized by the display having dark spots on a solid white screen, or not lighting up entirely and only being visible when you hold a flashlight up to the screen.
Replacing the LCD display assembly (LG LC320DUE-SFR1) from the entire touchscreen monitor assembly is the easiest method. This only requires you to remove the outermost metal case and touchscreen glass, and swap the LCD display inside.
For the adventurous it is possible to replace
only the backlight LED strips. This requires complete disassembly of the monitor down to the LCD glass itself, but is significantly cheaper.