First you need to find out what the graphics cards is weather its Onboard if so what kind etc.
if its seperate you need to find out if its by eg Nvidia or Ati etc. then look on the website.
Alternatively look on the NEC site and see if they have a page where you can download various drivers that come with there laptop..
Last thing i promise. Have a look if u got a restoration CD with the laptop then all the drivers should be on there.
Good luck, if you need further help give me a shout.