You can try to fix a black screen on an LG monitor with these steps. The first step is to power off your monitor and unplug it from your computer. Now, press and hold the power button for about 30 seconds until the monitor turns off. Finally, plug it back in and wait a few minutes for it to boot up. After that, you may need to reset your computer's BIOS if your monitor is not turning on. But If that still does not solve the issue, you may need to replace your monitor. I think the monitor is completely black and no way to fix it.