This is a tough one.   I've lost my sound..   All the tests I run say there are no speakers attached or internal. There is no speaker selection or sound control app and and no inputs or outputs listed.  The device manager shows no realtek sound drivers despite repeated installs. There is a hi-definition audio driver listed but I believe that is the HDMI channel. This all occurred after I installed optane memory. I did that because of  errors reporting no optane memory during file transfers.  How do i fix this?