The fact that an activated Windows OS license becomes unactivated only means that your computer is asking Microsoft, at every single reboot, or routinely, is this license is legit and depending on the answer whether it should destroy itself.

This is appalling in every sense. Governments should sue Microsoft for their anti-customer behavior.

If you need a new computer with Windows on it, my advice is to buy it along with a Windows 8.1 license DVD, and then reformat that new computer's main disk and install Windows 8.1 on it. Problem fixed.

[Update Nov 10] : Microsoft has publicly said the problem is fixed and should be fixed for any customer within 24 hours without having to do anything. So this actually reveals that your computer is phoning home every 24 hours. Now, you can keep using this surveillance tool, just so you know what you are doing.
I sense that perhaps Microsoft will deplete the availability of Windows 8.1 OEM license DVDs, just in case the fraction of users who know what they are doing change their mind about Windows 10 and install Windows 8.1 only to stopped being harmed by Microsoft, a corporation that should be sued up their ass. Governments out there, please act! it's time !