Ah, right, many thanks!

With me here, I noticed that Windows is using the first 5 characters of the mail address of the MS account.
That may not always be desirable.
e.g. for hotmail I used a...

Over time I had a few retail licenses for Windows 7(seven) Pro and one Windows 10 x64 retail.
In the Windows Explorer->Help->About, they show different users under licensed to.
One old (blabla at...