noshali,
Understand that it's not just the monitor but the video card as well that's causing you headaches. If the listed possible resolutions in control panel stop at, say, 800x600 then there's very little you can do to display widescreen content. The only possibility is a more up-to-date driver for the video card. Even though the monitor is capable of displaying 1280x768, the video card is limiting your display. Also, make sure that the monitor is recognized by your system. 90 percent of the time Windows will identify a monitor as a "plug and play monitor". See if there isn't a specific driver available on the net for the monitor. I've done this in the past to deal with similar problems.
Good Luck,
Chuck