Sometimes, the video card does not "see" what the monitor is specifically - it just knows to output a signal at the most common resolutions. The LCD should have come with a CD (or can go d/l from the website) that tells the computer what resolutions the monitor supports.
If that 1600x1050 res is not available in the directions skellyo posted, you'll need the drivers. If it does, you're good to go.
Be aware that unless you have one heck of a powerful video card, you are gonna definitely want to turn down the resolution if playing any of the current 3D PC games (from within the game video settings, not your desktop). The power to render high-Q video at 1600x1050 is not insubstantial and you may get very low frame rates. If you don't play games, disregard this whole paragraph.