OK, so you have two video outputs, correct? ONe on board, and one graphic card output, right?
Take the Graphics card out, and plug your monitor onto the onboard graphics, and load your OS. Then, after you have a stable platform, insert the graphics card, and make certain the drivers are correct and loaded.
Right now, what would you expect to see on the screen without an OS to boot to? There is nothing to display!
BTW, did you provision a partition for the drive? Did you mark the partition as active? Is the active partition set to your boot order in BIOS?
You could be dealing with more than a video issue!
It's kind of fun to do the impossible! -Walter Elias Disney