There is another way around, install VNC viewer in the laptop and a VNC server on the desktop. Attach both computers to the LAN, just remember the desktop's ip address. Then you can access it using your laptop's monitor, keyboard and mouse. All you need to plug in the desktop is the power cord and network cable.

Anyone manage to do this recently? I have a crappy old vdu for my desktop and currently don't have the money ("have more important things to buy") to buy a new monitor

you can share your laptop monitor into your desktop monitor by using desktop remote server....

:)