Please try all of the steps below.
If the monitor still does not work, then reply to this ticket.
1.  Check to see that the cable between the monitor and computer is securely connected at both ends. Push it in at both ends.
2. Check to see that the monitor's power cable is securely connected to the monitor and to the power socket. Push it in at both ends.
3. Turn the monitor off and on.
4. Restart your computer.