RE: Audio no longer working. NVIDIA Card can't be detected
If the Audio driver installed on the system:
Please check if the Nvidia driver is listed in the Apps & features or Programs & features. Type Setting onto search box, select Apps, and then look for Nvidia driver. If there is one, uninstall it. In device manager, expand Display Adapters, click View, and then select Show Hidden Devices. If the NVidia driver appears, do the same steps as Audio driver but instead install latest NVidia (Video) driver.