If it is still in warranty call the manufacturer.
if not give more info [email protected]
. May be somthing simple like a cable
shutdown computer unplug then disconnect the video cable on the computer from the monitor, plug monitor back in and turn it on, there should be a display that says no video source within a few seconds, if unit is working properly. shutdown and connect video again and then reboot computer. sometimes it just takes a compleat power disconect to reset things,