If its small enough that you can't move the box to change the resolution, reboot your computer and press F8 several times around the spot where you see the WindowsXP screen. That will take you to a menu with several options. Pick the one to start up in VGA mode. Then you will be at a resolution that while large, you will be able to work with it. I think you can go up to 800x600 in VGA mode. But regardless you will need to reinstall video drivers, either download them or get them off the CD that came with your video card.