I can't find anything faulty on the Benq PCB board and the monitor itself has gone dark. Not sure if it's working; any guide to fix this myself?

Answer:
One way to find out if the LCD monitor is working is by shining a light or torch straight at it. You'll see a kind of dim faint image as the light is reflected off the white thing behind the LCD. To repair your monitor, refer to the guide below. It's got schematics and diagrams to do it yourself.