Check out the video, you can just install windows 10 & run it with out activation key

you have a watermark & a few personalization options don't work
I remember Windows 7 and 8 you can install without a key. But I seem to recall it worked for like 30 days and then it won't boot until you gave it a key.
The thing about Windows 10 for free, here is how I see it. They rather you pay for it and most people will anyway. But for whatever reason you won't, they still rather you run Windows 10 for free. Two reasons I can think of. One, it is better for MS for you to have for free than you run Mac OS, *nix or something. And two: MS, NSA, etc. has backdoors in Windows 10 that they could break into your computer anytime they want to. This is true of earlier Windows too, but they are much better in Windows 10.
Speaking about breaking into your computer, this is true of Chinese made chips too. I forgot what year they started putting backdoors into their chips. Something like 2003 rings a bell. This is also why our military doesn't use anything with Chinese made chips in it.
Windows 95 key was easy. All numeric and if the number was dividable by 8, I believe that worked. Or you could use the beta key which was all zeros. MS meant to remove the beta key before the retail release, but it never happened. OEM versions, the beta key wouldn't work.
And like
TrollDragon, my four Windows 10 machines doesn't need a Windows 10 key. I read this is true because of TPM. I could clear it or disable it. But Windows 10 will then want a key which the manufacture didn't provide. Nor can you install anything but Windows 10 on these machines I've heard (unless you turn TPM off). I tried booting Linux on one of them and the TPM blocked it. Which stopped me from cloning the drive.
