Suddenly found I had lost my sound on my Windows 10 system running on a Gigabyte Z170X Gaming 7 G1 motherboard with a built-in Creative Sound Core 3D Quad-Core Audio + SBX Pro Studio Audio Suite. Sound info in the control panel has VGA Display-4 (NVDIA High Definition Audio) and also Speakers Sound Blaster Recon 3Di. Have tried switching between these two audio outputs and have also restored system to previous date but to no avail. Have checked the drivers under device manager and they seem OK. I've usually got round such problems by restoring the system and reinstalling drivers but this has not resolved my disappeared sound. I know the external sound systems are OK as the screen which has speakers incorporated plus keyboard etc are shared through a Belkin switch with a second PC whose sound is OK.