Have you told the nvidia software to enable the second screen?.
Yes. My NVIDIA Control Panel recognizes the primary by name and #1 and the secondary as #2 by name of ProView PL713b.
In Windows Control Panel/Display Settings it recognizes the primary by name and #1, but the secondary it recognizes by Generic PnP but does have it as #2. I don't think that would make a difference but, if it does, I have no idea of how to change.