Third Monitor isn't being detected

[MrAltDennis]

I recently moved my computer and acquired a new monitor. I plugged it in but in settings the third monitor will not be detected. When i first checked the monitor wasn't in device manager but i would be wrong. The awkward thing is that when i open bios the bios menu opens on my main monitor and the one that my computer doesn't detect. How do i make the computer detect the monitor?

 

[MrAltDennis]

i more or less figured it out. I just changed the wire which worked for some reason. I dont know why it fixed itself but it did. There is, however, an odd line down the screen. The best way i can describe it is as a verticle column of thin horizontal black lines that only shows up on white backgrounds (like a google webpage). The column is a bit off center to the left if that helps. Its pretty annoying and if anyone could help me get rid of it id be very greatful