My computer wont display anything on the monitor.?

I'm building a computer out of old miscellaneous parts from my my dad's old computers. I have a motherboard with the original ram and processors. I have the hard drive, optical drive and all the other necessary components. My problem is that the motherboard doesn't inherently provide any port out for display, such as a VGA port or anything. So I've tried using half a dozen various video cards, and I still can't get anything to display. All the lights are flashing, fans spinning, the optical drive and hard drive are whirring. Can anything give me some suggestions on what to do?