The most likely cause of a camera unpredictably switching off would typically be associated with the camera's driver or hardware malfunction. Since software issues have been ruled out, checking the driver in Device Manager would be the most logical next step. Updating or reinstalling the driver can potentially resolve the issue. Checking BIOS settings might be another step, but it is less probable that settings there would cause unpredictable switching. Inspecting the camera settings in the conferencing software has been ruled out, and checking the antivirus would not generally impact the camera's functioning unless there is a very specific setting or interference, which is less common.