I’ve been running Windows 10 since July, and I like it. I performed an in place upgrade for both of my computers, so I thought it was high time I did a clean install. I had tried in the past, but I could never get past the activation. It was hard finding information to explicitly say how to clean install windows 10 with a windows 7 ultimate product key.

After a failed clean install with an older version from July. I ended up calling Microsoft Support, they were fairly clueless; probably a situation of the left hand not knowing what the right hand has done. I did acquire one very useful piece of information however, and for the sake of search engines I will spell it out explicitly for you.

To activate your Windows 10 clean installation with a Windows 7 Product Key, you must use and install Windows 10 Build 1511.