That lighter screen with no image is from the monitor detecting a signal but no image. Say if it's cycling though the connections or if the video card is saying it's connected and working but not sending a full video signal. Try resetting the monitor settings to default, install the latest BIOS, chipset, power management and video drivers for your system, and see if it does the same thing.
You can also set the power management settings in the monitor itself to turn off after so long without a signal if you have not done that.