I assume you mean 20WMGX2, as I that was the only one I could find on their site.
Download the driver:
http://www.necdisplay.com/cms/docume...rs/20WMGX2.ZIP
Usually windows defaults to its native PnP driver for monitors and queries display information from the monitor.
It could be that with the new card it is unable to determine the supported resolutions, however using the manufacturers driver will ensure the display is being driven at the proper specs & resolution.