Stopwatch Privacy uses your webcam as a motion detector to detect approaching snoops, then...

StopWatch AUTOMAGICALLY hides and mutes your Top Secret windows, webcam chats, movies, sports, computer games, and more. 

You can make just one app dissapear, or many.
Compatible cameras
All webcams (StopWatch Pro & Ultimate)
All wireless IP cameras (StopWatch Ultimate)
How does it know when to hide apps?
It uses your webcam and/or wireless IP camera to detect motion.
Or, you can set its Inactivity Timer for one or more minutes.
Or, you can just type "Alt-x" on your keyboard when someone enters.
In what ways can it make apps disappear?
StopWatch makes them dissapear from your screen and your task-bar.
If you like, you can even require a password before they'll reappear.
It can...
   Minimize them, instead.
   Shut them down completely.
   Mute your speakers.
   Lock your screen.
What apps will it make dissappear?
Any Windows-desktop program you tell it to.
Fullscreen movies playing from browsers.
Fullscreen movies playing from the major video players.
Fullscreen Skype chats.
It hides ONLY what it's told to.
  --Which is a cool thing about StopWatch:  Everything else remains on your screen ready to use.
It will hide all Windows 8 and 8.1 regular desktop apps like Skype, browsers, Microsoft Office, Adobe products--everything.  We have chosen not to hide Windows 8 and 8.1 tablet-side metro apps unless they become  popular in the future.

After you make an app disappear, how do you make it reappear?
You simply click the little StopWatch icon by the clock in the lower right hand corner of your screen. 
You can...
   Make hidden apps reappear one at a time, or...
   Make them all reappear at once. 
   Choose to require a password to reveal certain apps.
   Choose to require a password to protect StopWatch itself.