Troubleshoot a Blank PC Monitor
To troubleshoot when you see nothing on the computer monitor, check the basic hardware first: Is the monitor turned on? Is it plugged in? Is the monitor properly connected to the display adapter on the console? If the monitor has dual inputs, is the proper one selected?
A computer or monitor in Sleep (low-power) mode shows its power-on LED in an amber color rather than in the normal green. If you still don't see anything on the monitor after you wake it up, the problem is with the video signal not reaching the monitor.
Press the monitor’s menu button. If the monitor’s menu appears, the monitor is fine and the problem is with the display adapter.
When a monitor has dual inputs, be sure that the proper input is selected. This type of checking is the same as my general check to see whether it’s plugged in advice, but usually you need to press a button or switch on the monitor to ensure that the input is coming from the proper connection.
Sometimes it helps to unplug the monitor cable and then plug it back in. When the issue is a power-supply issue, such as when the monitor’s power light doesn’t come on, unplug the power cord and plug it in again.
A monitor is never something you should try to fix on your own. Never open a monitor’s case.
When a monitor is dead, throw it out. Do so properly, according to whatever rules govern the disposal of computer equipment for your locale.