Dell Webcam Central is the main application used by Dell laptops to provide functionality to the built-in webcams. Please open Device Manager (Start > Run > devmgmt.msc) and locate any items that have a yellow exclamation mark. If there are items with this mark, right click them and choose Update Driver and perform the automated operation for drivers installation. You can also uninstall Dell Webcam Central and perform a new installation. If you are prompted to accept a driver installation, please click OK, or you will encounter problems like the one you're having.