I have never seen any laptop that allows you to use its display only by connecting it to another computer that actually generates the video signal. I doubt it can be done easily. The closest approach I can think of requires that both computers be running. Then you need some sort of video signal input on the laptop that matches an output from the desktop's video card. For example, if you can generate an analog NTSC Composite Video signal (like the Video Line Out signal from a VCR) on the desktop and put that into a NTSC Composite Video input (capture) port on the laptop and then run the capture software, you might get to see what you want at limited resolution. But I really doubt that it what you want to do.