you can open the laptop and remove the flex connector ribbon cable from the web camera so its not plugged in to the mother board any more
Happiness is like peeing your pants... Everyone can see it, but only you can feel its Warmth!!
Paolo above me has a great idea, but if you can't take the screen apart...
Get a small drill bit and make an indentation or small hole, just above the camera lens. Use an LED flashlight at an angle to see the actual camera lens if it is under the same plastic cover that covers the LCD screen. Spray a little black spray paint on a piece of cardboard, then mix some 2-part epoxy next to it and mix in the paint, then use this to fill the indent - looks good, camera actually still turns on, but doesn't see anything.
I fully support this on any kids laptop - no good can come from having a camera.