In order to fix the issue, yo will need to uninstall and reinstall the webcam drivers. For this purpose, press Windows + Pause/Break key combination and open Device Manager. Expand the Imaging Devices list, right-click on the webcam driver and select Uninstall. After that, reboot your PC, navigate to Dell Support page, identify your computer model, select your operating system and download the webcam files. Go again to Device Manager, click Scan for hardware changes icon, right-click on the webcam device and select Update Driver Software. Use the Browse option to navigate to the installation package, select the driver and install it following the on-screen instructions. If this doesn't help, you need to get in touch with a Dell technician.