As Michael said, video boards or video subsystems in laptops don't have any "native resolution". However - your Nvidia video system does have a MAXIMUM resolution. If that MAXIMUM resolution is 1280x768 and your new monitor is 1680x1050, your video system will never fill the screen of the monitor no matter what you do. New Nvidia drivers won't help. Depending on how your monitor works, it MAY be able to upconvert the incoming 1280x768 to fill the screen but there might be geometric distortion. What you really need is a video system that supports the resolution of the monitor so you get a workspace that is not compromised. Your Nvidia control panel (if you have Vista, you can right click on the workspace background to bring up a pop-up menu that allows you to open the Nvidia control panel (not sure if that works with XP or not) will have a resolution slider in it somewhere. If the highest setting for that slider is 1280x768 - your current video system can't make enough resolution to fill the new monitor - unless the monitor has tricks up its sleeve.
To be fair to the intent and content of this thread, what you are asking about really has nothing to do with display calibration though - so perhaps you need to find a forum the specializes in PC video systems if the info you've gotten here doesn't get you headed in the right direction.
