I am working with a M410HD. We are having problems with the VGA input. When plugged into a laptop. One we have used many times in the past. It detects the input signal and switches to a grey output screen, not displaying the contents of the desktop. When you go to the input selection menu screen the VGA is disabled and there is no option to enable it. The VGA is greyed out. I have check the resolution output and made sure that it is within range. Any thoughts?