A laptop's external webcam software is running, but it shows no image or video.

https://www.lifewire.com/fix-it-when-webcam-is-not-working-4588517

If a laptop's external webcam software is running, but it shows no image or video, the first step the technician should perform is to reseat the webcam. Reseating the webcam involves disconnecting it from the motherboard and then reconnecting it. If this doesn't work, the technician should then check the webcam drivers or software. References: CompTIA A+ Certification All-in-One Exam Guide, Tenth Edition by Mike Meyers (Page 502)