4 separate win7 upgrades, 3 have the same 10 key

I have 6 pc's on my home network, all but one was running Win 7 Pro, I have upgraded 4 of them to win 10.
All were retail keys, I was checking the key today so I can have a hard copy, (a few years ago I had a HDD crash and didnt properly back all 8 keys up, and lost 2), any way, I used the newest AIDA64 to check the OS goodness to get the key, and the only one that is different is my PC, I also used magic jelly bean, they both report the same thing...

Is this something to worry about??? All pc's are activated..

It's normal for the Windows 10 upgrades, as there aren't unique license keys being given to people who use the free upgrade. There are a small number of communal keys that are given to everyone making use of the upgrade. Microsoft isn't authenticating the upgrades based on their serial keys, but on the system hardware which they're installed to.

If you ever want to transfer your retail Windows 10 license to another PC, you'll first have to install Windows 7 on the new PC, then upgrade it and authenticate it with Microsoft's servers, then if you want a clean Windows 10 installation, format then reinstall using a Windows 10 ISO. After the new hardware has been associated with the upgrade once, then it will be recognized by MS's servers, and a clean installation will work. The serial keys given for the free upgrade of Windows 10 don't have much significance.

Ahhhh, ok thanks..

Delicieuxz said:

If you ever want to transfer your retail Windows 10 license to another PC, you'll first have to install Windows 7 on the new PC, then upgrade it and authenticate it with Microsoft's servers, then if you want a clean Windows 10 installation, format then reinstall using a Windows 10 ISO.

That is incorrect. If you have a retail Windows 10 license, then you also have a unique Product Key which can be entered when asked for during the Windows 10 installation. People who use the free upgrade don't get retail licenses, therefore they do not get unique Product Keys and, therefore, when they do a subsequent clean install on that same computer they should skip entering a Product Key because they do have a unique one to enter. Since a retail license also has a unique Product Key that can be entered during the install, there is no need to do a Windows 7/8/8.1 upgrade first.

People who use the free upgrade only get the generic free upgrade product key which is used along with the Hardware ID to create a unique Installation ID which is used to activate the Windows 10 that came from the free upgrade. That generic Product Key should not be entered when doing a subsequent clean install. When Windows 10 contacts the activation server with the Hardware ID, the activation server will recognize that Hardware ID as a previous free upgrade and will provide the generic upgrade Product Key which then creates the same Installation ID as before which then activates that install of Windows 10.