Here is a youtube tutorial on how to set up dual monitors in Windows 7. This is strictly a tutorial if you have a video card already installed with the capability such as a laptop with an extra VGA female input or your desktop has two inputs be it VGA, HDMI or DVI. If you need to actually install a video card this is not the correct turorial. This is simply how to set up installed monitors.
This youtube video is best viewed in fullscreen mode with 720p HD.