Automatically Disable 2nd Monitor When Gaming?

I Googled some, but I thought it might be best to just ask here.

Is it possible; through nVidia Control Panel, Windows, or otherwise; to automatically disable my second screen when I start playing a game? I don't think it's terribly affecting performance, but I would also like to know for sure that I am getting the maximum FPS possible. One screen is 144Hz, the other is 60Hz, and the 60Hz gets some scan lines in it when I am gaming, so I imagine the GPU might be doing some work it shouldn't have to.

Any and all advice is welcome.