Hit the power button which is located below the screen of the monitor. The green light should appear If monitor is working properly. If no light appears, this indicate that you need to replace power supply board.

If there is no display on the monitor, then you need to modify your monitor's settings. The problem is either caused by the connections between your computer and the monitor or there is something wrong with your screen.You can adjust the settings by pressing the Menu button in front of the monitor. If nothing appears, you will more likely need to replace the display.

The flickering might be due to one of the capacitor not working properly . If this is the issue, then you need to replace the capacitor.