If you recently installed the OS, you need to make sure that you downloaded and installed the latest drivers for your webcam. These can be found on the manufacturer's website. If you have the latest driver installed and you still can't use the webcam, then swipe from the right side of the screen to enter the Start menu. In the search bar type msconfig and press enter. In the new window go to Service tab and make sure to check the Hide all Microsoft services option from the bottom of the page. Next, go to Startup, and make sure that all programs related to the webcam are not selected. After you did this, press Apply and OK. Reboot your PC and try making a video call using Skype. The error shouldn't appear anymore.