Well, when this April Microsoft update was installed (for us) in May, I tried the link I received from the forum to reinstall the IDT software. It said it was no longer compatible. Then I went to Microsoft forum to see what they could do. I could do a lot of stuff to 'go back' which, for many reasons, I was reluctant to do. We've been without sound on the desktop. A couple days ago Windows had more updates for this 1803. Which are installed. I thought that would fix the sound it didn't. So I posted here.
I re-read my previous question from September. I tried the link for the IDT driver again and today it worked!! We have sound again. Thanks, again, to Paul Tikkanen for providing the solution back in September!