When I first built my pc, I, like everyone else, plugged one of my monitors into the graphics card. The other, however, is plugged in via a USB hub. When I try to plug the second monitor into the computer itself, the monitor sees that it was plugged into something, but doesn't show anything on the screen. I went to the display menu in windows settings and tried to detect another display, but it said there wasn't any. My monitors only have DVI-D ports on the back, so they're connected to a converter that goes to HDMI.