It's possible that you simply need to reinstall the drivers for the webcam/microphone (both devices use the same driver). 

To do so, please follow the guide below: 

1. Right click on the Start Menu, and select "Device Manager". 

2. In the new window, find and expand the section called "Cameras" or "Imaging Devices" (one of these two will be an option) 

3. Find the webcam driver, right click on it, and select "Uninstall". 

4. If prompted to uninstall any software, agree to it. 

5. After the device is uninstalled, restart the laptop. 

6. Once the laptop restarts, the camera should function as intended. 

If there is no "Cameras" or "Imaging Devices" section in the Device Manager, please run Windows Update to make sure your laptop has all the latest updates and drivers, then check whether the webcam is functioning again.