Did you enable the Privacy setting to allow apps to use your webcam?
https://www.top-password.com/blog/enable-disabl...
https://privacy.microsoft.com/en-us/windows-10-...
Try the Hardware & Devices troubleshooter at Settings > Update & Security > Troubleshoot.
Try Updating the webcam driver from the PC maker's Support Downloads webpage for your exact model. Install it even if it's the same or newer than the one in Device Manager reached by right clicking the Start button.
Also compare all other drivers including Chipset, display, sound, etc to make sure you have the latest on the PC maker's Support Downloads web page.
Right click Start button to access Device Manager, locate Webcam device (if necessary from View tab Show Hidden Devices), on Driver tab see if Roll Back is available, if not try Update Driver, first automatically, then Browse, then Let Me Pick to try all previously installed Drivers.
If these fail try to Uninstall the Driver, restart PC to reinstall.
If this was caused by Windows Updates then you can check which were installed at Settings>Update & Security>Windows Update under Installed Updates, then uninstall them from the link there, and hide with the Hide Updates tool downloaded from here: http://download.microsoft.com/download/f/2/2/f2...
You can also use System Restore to get before the problem began, then check for Updates with the Hide Update tool and hide them: http://home.bt.com/tech-gadgets/computing/how-t...
Go over this checklist to make sure the install is set up correctly, optimized for best performance, and any needed repairs get done: http://answers.microsoft.com/en-us/windows/wiki...
Start with Step 4 to turn off Startup freeloaders which can conflict and cause issues, then Step 7 to check for infection the most thorough way, then step 10 to check for damaged System Files. Then continue with the other steps to go over your install most thoroughly.
If nothing else helps what I'd nstall Media Creation Tool from this link and choose Upgrade This PC Now: http://windows.microsoft.com/en-us/windows-10/m...
This is the most stable way to change to the newer version and because it reinstalls WIndows while keeping your files and programs in place, fixes most problems. It also brings all Windows Updates to date.
If there are any hurdles during install then these steps can overcome them: http://answers.microsoft.com/en-us/windows/wiki...
You can monitor the Windows 10 Blog here to get notified of the exact date for release of Spring Creators Version 1803 which is soon: https://blogs.windows.com/windowsexperience/#ut...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.
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