I tried doing what was suggested in the article above, double clicking setup exe and choosing nothing to keep. Instead of getting a real clean install, there was an Old Windows on C drive that had some files from my previous install. It even had Windows 7 in parenthesis next to system backup and restore. There is no windows 7 restore point or system image. The only image I made was for 10 before I tried the USB clean install.
I'm not sure, but perhaps when installing 10 from media tool to USB stick, I didn't check Boot in the Burner software.