Dear..

Hello there:
This is usually not a good sign
I will give you a couple of things to try out first ok
(1) you may want to try the monitor on a seperate computer to see if it will work if not than the monitor needs to be repaired.
but if the monitor will work on a seperate computer than this just means that your video card on your computer is either loose or it is not working to test this try these steps
you can try to remove the power cord and open the case and remove the power supply cord that goes to the motherboard than press the power button of the computer for 15 seconds and than if you have a reset button press this button for 15 seconds than plug the power supply cord back into the motherboard and try to reboot the machine and see if this will work if not try this
(2) with the computer unplugged remove the video card and clean the gold edge with rubbinbg alcohol and let dry than reinstall than reboot the machine if still nothing than you will have to get a new video card.
*** NOTE*** if your video card is built to the mother board this is a common thing cause they dont last forever so just get a new video card and install and connect the monitor to that one and not the old one ok?
so please try these solutions and you should be all right
best regards michael.