We have a Dell Optiplex 320 that has been running fine for about 6 months. Yesterday the monitor went black and would not turn back on. The green LCD light stays green; if I unplug and plug back in the power cable the monitor turns back on for a second then goes back to black. I tried a new monitor and new serial and power cables with the same result.
When I try to reboot the monitor it starts going black at POST. Does this point to the video card?
When my video card failed, monitor wouldn't even give green power LED. Yet, pressing the 'menu' button would give a monitor internal response visible. Sounds to me like the backlight has failed.