i shall post what I wrote on a different forum and somebody might be able to guide me:
Hi all, well had no sound yesterday for some reason and it's been fine using HDMI from my Asus PG279Q for years. Checked settings to find I had lost audio control from sys tray. Could not see Nvidia control panel either ?? then couldn't find realtek drivers ?? WTF ?? reinstalled all drivers .. still no sound. Swapped monitors as well to count out monitor faults and cables (none found). Plugged in an optical cable to mobo spdif and ran it into amp .. no sound! .. installed older 2.81 realtek driver and managed to get sound from youtube videos but if I try to play mp3's then it would just come up with no audio device connected to play this or codec error. Did a windows repair and I now have audio on every type of file (mps, flac, WMA etc) along with movies(via optical out only). But I still cannot find any options for controlling anything more than volume .. can anybody give me advice on where to go from here please to get back HDMI sound from my monitor and to get back surround sound (at least 5.1) from my mobo optical out

Win 10 x64
Mobo Asus Maximus viii Extreme (latest bios update)
GPU Asus ROG 1080ti (latest driver)
Monitor Asus ROG PG279Q
Realtek driver 2.81