I have been given two win 10 pro iso files, one downloaded from MS Techbench while the other through the use of Media Creation Tool. The file name of the iso files are identical. My query are: - (1) Which iso file should be used to upgrade Win 8.1 pro? (2) How to kick-off the upgrade process; i.e. install within Win 8.1 pro or do a clean install such that on completion system activation is done automatically. Directive will be appreciated.