The only way you can find a driver is to visit the NEC (Japan) website... you can find it's link from this page:
However, realize that the Japan link is in Japanese and the driver may also be in Japanese. If you don't speak the language you will need an interpreter.
Or..... you can click the HOME button (upper left of this page) and click on the link for the new beta Driverscan 2011 software. Download, install, and run it.
Or ..... open Device Manager, double click the graphics/video device, click the Details tab, and give me the hardware id string that begins with PCI\VEN. (1st. line of text only).