Hi,
I have a Dell 5289 laptop and faced the "camera not found in device manager" issue recently after a long windows update on Jan 22. None of the suggested "fixes" worked and I thought that the camera hardware had some issue and may need replacement. But being a tech enthusiast for over three decades I decided to remove the updates but still the camera was not showing in the device manager!! I then reflashed the BIOS via USB drive. Lo and behold !! the camera was now in the device manager and working fine !!
So, microsoft please do check your updates thoroughly befoe they are released to the public....nobody wants nuisance.