Samsung 226BW Problem?

[Ace78]

So I have a Samsung 226BW LCD, about 3 years old, worked fine till this morning. I see the blue light on which means its on but the screen is black... I turn it off and turn it back on, it will show the desktop for like 1 sec and go black again. The light on power button is on (not flashing) indicating that it's receiving signal from video card. When I plug in other monitor it works fine, so it should not be display card. Any ideas what could be wrong? Thanks