Actually i am not sure if it is a problem or it is like that. I have a samsung syncmaster 19'' LED monitor. When my computer goes to sleep mode or when i shut it down, my monitor screen does not go black instead a box containing text- Check signal cable/Analog; use to pop up and it does not turn off. I have to touch the power button every time if want to make the screen black. But why ? is it a problem?? any solution? Please help.