The open VGA port you have, is that the MB port? If it is, it may have been turned off in BIOS when your video card was installed. That was the case when I had a video card installed on my system. Just go into BIOS and check that onboard VGA is active. Hope this helps.
Hooking up a 3rd monitor so I can play TF2 on 3 screens. I hooked it up to the open VGA port on my computer, but it says that's an unsupported configuration, and that I must hook up the monitor to the graphics card. With the DVI and VGA already taken by the other 2 monitors, all I have left is a female S-Video and a Male VGA from this monitor. Can't find a converter anywhere, help?