I have a Dell XPS and when I try to use webcam it's showing "Close other video streaming application". I cannot figure out what the other application is.
Go to Start > Run > type msconfig and navigate to Startup tab. Deselect all the applications in the list and reboot. When the system loads, try to access the webcam with the application. Then use the same menu to check one item per reset. This way you will identify the application that is interfering with your webcam.