The only way I think you could do this, would be to connect a TV-out connector from your VGA card (if you have one) to Video-In port of another computer or a DVD recorder. I've wanted to do the same in the past for making tutorials, but never got around to doing it the way you want to. I can now do what I want using the BIOS of a virtual machine. When all is said and done, taking photos is probably the best bet ;p