Did a new install using the Microsoft WIndows 10 media creator tool (Win10Pro 1803 version). When we did the install, Win10 identified the old one and created a Windows.old folder and stuffed the entire contents of previous install there. Once complete, we just moved contents from his old profile back to the new. We could of copied over his old profile, but we did something different this time... (below)
And here are some lessons learned ...
1. We use Origin and Steam for most of our major games. Both Steam and Origin also use the cloud to backup in-game profiles, settings, and all other games settings/in-campaign saves.
2. When we were first prompted after the install was complete, we used his Microsoft account that he also uses for XBox and Minecraft.
3. Microsoft had already attached his WindowsPro 10 key to his account profile - so we didn't actually have to re-enter his key.
4. For all the Origin and Steam game installs, all we had to do is reinstall Steam and Origin, and point back to the original install directories. Origin verified all the previous games while Steam just went "ok - here are your games again". That was it. No game re-installs required. Saved us hours of reinstalling software.
I'm torn about the fact that Microsoft already knew to attach his Windows10 key to his Xbox account. Torn actually - it's a good thing but also a little creepy. ¯\_(ツ)_/¯