You can do it this way. If you have Windows 7, right click on desktop, click screen resolution, and click on display and click extend displays. Now you can drag documents from you main display into the other display (the extended display).
You can also do this from you graphic's card control panel. I have ATI, and I prefer to do it through them as I can only play games on another display if I do it through there settings. You can just go to desktop and display options, right click on your second display and click extend display. Or something very similar to that.