Then it could be a hardware failure. Last year I found one that had become unplugged. That's not to say that is your issue but since it's not in device manager that's NOT a good sign.
Hope you have a warranty on this thing. Out of warranty costs seem to upset everyone.
I have an HP Pavilion Entertainment laptop type 9289ea with a built-in webcam which has ceased to function since, I believe, either Microsoft or HP threw a patch at me which I now cannot find, I'll blame Microsoft.
HP have tried to fix to no avail, finally recommending I perform a system recovery, which I am loath to do because on the c: disk is the OS and a load of my stuff which, by the way HP recommend installing apps on to the d: disk, but did I listen.....nah.
There is a recovery partition on the e: disk which we are advised to steer clear of, and I have.
I cannot find the webcam entry in the device manager either.
Any help would be greatly appreciated.