I want to be sure this is the problem.
Was there any other side effects preventing the screen from showing? How did you resolve it before the new graphics card?
I tried a different monitor and different ports on the graphics card. When that didn't work, I knew it was the GPU that was the problem. That, or the slot on the motherboard. Obviously I tried a new GPU first because that would be faster than getting a new motherboard.
When your monitor says "no signal," you can pretty much assume your video output's the problem. Unless something like the wiring from the video plug on your monitor to the internal hardware of the monitor got messed up.