Double check your graphics card drivers here
http://www.nvidia.co.uk/Download/index.aspx?lang=en-uk
As far as I can see they should be 347.52 released on 10/02/2015
If you use the Nvidia prog in Control Panel you will get better troubleshooting possibilities in there. Including dxdiag for DirectX.
Hows the new monitor connected, maybe an issue there?
Generally, altering the 'gamma' and 'windowed mode' or 'full screen' in game settings normally works.
I have no experience with the game so cannot advise, but suggest you visit their forums.