Need help with my monitor. When I connect my monitor with VGA cable it turns on but after a few second the monitor goes blacks screen. The pretty sure my monitor is open because when I remove the VGA the monitor display a "Cable not connected". When reconnected with the cable it turns on again for some second then black screen. I have tried changing the power and VGA cable but it does the same thing. Also when I turn of the monitor and re open it, it again open for some second then WHALA! black screen again.