Hi Gabby
I had the same problem
I was a bit disturbed by this I always keep a lens cap on my web camera when not in use. Not only does it stop spying but keeps the lens clean.
If it was a youtube video, go back to the video, and right click
a pop up box displays abode flash player privacy
allow s.ytime.com to access your camera & microphone.
Click on the privacy tab, that is the one where the computer has a big eye watching you, and make sure the settings are set to "Deny" and "Remember".
I did a search on google and found a link
http://www.keiths-place.com/blogs/keith/2008/stop-youtube-sytimgcom-video-camera-spyingHope this resolves the problem
Tony