Having issues setting up a third screen.

[feastfox]

Hi there I just got a desk big enough to allow me to have three monitors set up. I plugged them all in, but the third and newest monitor is not working.
Hardware: 2x MSI NVidia GTX 970's and Windows 7 Ultimate
My computer knows its there because its saying 'another display not detected' however if I go to the 'multiple displays' dropdown it says 'Try to connect anyway on; VGA'
What could be my issue?

 

[JimF_35]

What are you using to connect this monitor: Display Port, DVI, HDMI or VGA? Are you running through any convertors like DVI to VGA? What us the make and model of your Monitor?