There's also no where to 'buy a license key' because the entire point of this is to get rid of them.

install media for Windows 8.1 and download the ISO for the latest tech preview build of Windows 10 (9926). I don't have a previous version of Windows, all these guides assume you came from a previous version, rather than fresh install. OS is made by Bill Gates great really performance perfect only thing you need to know is never made upgrade turn off all updates called feature upgrades don't allow to do it upgrade Windows 10 if you get upgraded it won't use 0.9GB RAM like my Windows 10 by default uses only 0.9GB upgraded at least 2.7GB or most latest patch 5GB RAM to run Windows core you won't be able to play games like GTAV. If you want to reinstall Windows 7 on your computer and have a valid product key. To fix this, you'll need to go back to your previous version of Windows, make sure the previous version is activated, and then upgrade to Windows 10.' This is because we weren't able to register your free upgrade entitlement with the activation servers because you didn't upgrade to Windows 10. If you performed a clean installation instead of an upgrade, you'll be asked to enter a Windows 10 product key or buy a new license in order to activate Windows 10. In order to upgrade to Windows 10 using the ISO image or upgrade media you created using the media creation tool, you need to select the Upgrade this PC now option. Windows 10 Technical Preview Build 9926 is the first build of Windows 10 released for free to the public with the product key in the provided txt file.

'You created media and performed a clean installation of Windows 10, instead of first upgrading from your previous version of Windows That's great and all, but even from Microsofts site that you just linked:

Windows 10 9926 product key