So it reaches the P.O.S.T screen and nothing from there on? Or it's just blank from the get-go?
Plugging your DVI cable into the board would mean you would bypass your graphics card completely, it would be using Intel's integrated graphics to put a picture on the screen.
(I assume it's Intel, aside from their APUs AMD don't really have integrated graphics on their chips, therefore no way to connect to the board).
It's most likely just a simple fix, which port at the back of your card are you plugging the cable into?
Is it properly secured at both ends? (Monitor side also).
Sounds to me like it's either a dodgy cable, or you just need to press the 'Input' button on your monitor to cycle through to the correct one.
Does your monitor have multiple inputs too? You could try finding a HDMI cable and giving it a shot with that.