If none of any suggestions by other contributors solve this issue, kindly purchase a low cost webcam of any reputable brand, and connect to notebook/laptop.
I connect a low cost Logitech webcam to my Lenovo S340 notebook, it solve the problem immediately.
Several week later, I read from Microsoft Community (this community) and Lenovo's Community, about how other consumers solved this builtin webcam issue by "Pinching" the bezel (monitor frame) surrounding the webcam.
It worked for my case.
Hope this feedback helps other consumers.