Hi,
Are you using the Windows Camera app, and do you get any error message when you press Record?
Try to go to Settings, Privacy and Security, Camera, and turn on Camera access and Let apps access your camera. Then go to Settings, Apps, Installed apps, Camera, Advanced options, and select Repair. If the issue continues, select Reset. Also open Device Manager, expand Cameras, right click your HD Camera, and choose Update driver, then restart your PC.