Apple Cinema 30" Flat Panel Display Troubles

My Apple Cinema 30" Flat Panel Display is refusing to boot up - the power is on and the for the first few seconds after I wake the computer up, the screen appears, then it flickers and fades to black - even a total reboot of the compter (G5) it only comes on for a minute or two. The power light is pulsing as if the screen wants to start up - but it doesn't. I've tried replugging in all the connectuons, but that doesn't seem to do the trick either. Suggestions?