RealTek audio driver won't install

Hi: I'm unable to get sound from either the line out or headphone jack on my Opti 1050 mini. The machine is only a month old and worked when I first got it. I first did a chat with tech support who took over my computer and decided the problem was the motherboard. A service tech came out and replaced it. Alas, same problem Although my bluetooth Logitech headset shows up in Audio in Device manager, nothing else does. If I take out the bluetooth, the the sound control is X'd out and says no device available. Unfortunately, I'd not set up restore points when I first got the machine so am unable to revert to earlier settings.

We downloaded and Admin installed the latest RealTek that matches my system but it still doesn't show up in Device Manager. However, when I check processes and services, it shows up as running. When I tried installing an older version, it asked if I wanted to replace the newer version.

When I try to do a hardware search for new device and choose the default Windows realtech driver, it immediately crashes and reboots. Many of the troubleshooting tips recommend Uninstalling from Device Manager, then reinstalling. However, as above, the audio control is not even there (though it shows up in my other windows 10 machines).

Something's preventing the driver from connecting fully though it seems to be present and running. What now? I'll bump this back to Dell tech but am just trying to solve it here for now. I'd also like to avoid a clean install of W10 Pro.

Thanks!

George