Hi everyone , ive got a LG Flatron monitor model number W1934S the problem im having with it is i keep getting a black screen with the power light still on, but if i unplug the monitor lead and plug in back in i a get a picture for a moment then it goes back to a black screen, everytime i unplug the cable and plug it back in the picture is there but only stays on for a second then its back to the black screen

Check out for bad caps in the power supply first.

Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply, blown fuses, poor solder joints, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed LG and other monitors to get some ideas what to look for: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further and it will help out other people in the future also.
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.badcaps.net