No video on boot

[TheWickerMan]

I would first try and make absolutely certain that there's nothing wrong with the monitor. I'm presuming you checked the input voltage for the monitor and it matches the DC brick you found. Just cause the input connector fits, doesn't mean it won't blow the whole thing up. Also, after that's ruled out, visually inspect the capacitors on both the motherboard and the video card to see if any are bulging or leaky. Bad capacitors are pretty much the number 1 cause of failure in old hardware. If everything looks fine and the monitor is confirmed working, then it's probably the video card.