If you have software that allows you to adjust the screen for example to run across two monitors or a virtual desktop it may have just become corrupted.
Right click on the desktop and choose properties.. you should be able to re-set them to your standard resolution which should correct the fault.. if not, the best bet is to load windows in SAFE MODE, (press F8 as soon as the windows logo comes on screen) and then go into control panel and click on SYSTEM then DEVICE MANAGER. At that point uninstall the video drivers. the next time you reboot it should find them again and restore the settings to the standard setting
Lee Wainwright, September 2008
