Hi, I'm Bernard. I'm happy to help!
Based on your inputs, it seems that there might be a physical issue or a driver problem with the Camera. To sort out the issue, kindly follow the steps below:
Method 1. Check if the Camera has a slider to turn the camera on or off (Usually at the top of the camera)
Method 2. Check the privacy settings of the Camera (Go to Settings > Privacy & Security> Camera (Make sure that the Camera access is turned on)
Method 3. Roll back the Camera Driver:
-Press the Windows key + X
-Go to Device Manager
-Expand the Cameras
-Look for your Camera driver
-Right-click and click Update Driver
-Select Browse my computer for drivers
-Click Let me pick from a list of available drivers on my computer
-Choose an old driver or another driver name, then select it and hit next until it installs.
-Restart the PC and check.
Note: If the issue persists, kindly check the Lenovo Vantage app if the Camera is enabled:
Additional reference: