Go to their computer, move the cursor off screen to hide it.
Hit print screen, open paint and paste image and save to a location.
Right click on desktop and change background image to the save image. Right-click the desktop, point to View, and then click Show Desktop Icons to clear the check mark. This will hide the active icons and leave the image icons. Check the "Auto hide the taskbar" option in the taskbar properties section. What will happen is that nothing will work because they will be clicking on a image instead of his desktop.
Hit print screen, open paint and paste image and save to a location.
Right click on desktop and change background image to the save image. Right-click the desktop, point to View, and then click Show Desktop Icons to clear the check mark. This will hide the active icons and leave the image icons. Check the "Auto hide the taskbar" option in the taskbar properties section. What will happen is that nothing will work because they will be clicking on a image instead of his desktop.