OK.....Here's what happened. Window's installed KB4038788 again. But, after the 100% point, a prompt came up on the screen: "We couldn't complete the updates. Undoing changes. Don't turn off your computer"
After some time, my computer was up and running again with failed installation note in windows update. I realized that I still needed to download the new update KB4040724, which I did.
Then, I tried the update installation again and ended up with the "We couldn't complete the updates" prompt again.
Both updates [KB4038788 and KB4040724] failed. I downloaded the Window's Update troubleshooter tool and ran that. It wanted to re-download the 2 updates and so I left it at that for now. I need to get some sleep. I'll try that tomorrow.