If your webcam still fails after trying all the above, test the hardware itself. Boot a Linux live USB (like Ubuntu). If the camera works there, the issue is entirely driver/Windows-related. If it fails on Linux, the WB918LA module has physically failed, and you will need to replace the webcam ribbon cable or the entire display assembly.
If you have a driver file ( .inf , .sys ): Driver Camara Web Hp Oem Wb918la Abm 1 23