The best way of doing this that I've found is to use a freeware program from www.shareware.com called SnagIt. Snagit will take snapshots of your screen, window, or area of your screen, as well as make an .avi of your screen, window, or area of screen. If you set the area to your graph, you can create an .avi of it. That's the best and quickest method (with no programming).
Mark