FYI if you use the Media Creation Tool to perform the upgrade, you can choose the "keep nothing" option and it will perform a clean install (clean windows directory, not clean partition) but will preserve the license and bring it through to activate the new install. After the install you will have the Windows.old directory you can just delete.Finally nuked oldest daughter's laptop and installed from scratch. Had to burn an MSDN product key because I formatted the drive and didn't want to screw with bringing back old settings.