Get Windows 10 for free!

The new Windows 10 Threshold 2 release allows you to use a Win7 or Win8 Product Key to perform a clean install of Windows 10 and activate it.

If you have an unused 'Retail' Windows 7 Product Key (perhaps you ordered a Win 7 Install DVD + Product Key a few years ago) then you can use the same Win 7 Product Key to install Windows 10 (on the same system).

Note: This will probably not work after 2017-12-31 - see here.

For instance, I upgraded my home-made system from Win 7 to Win 8.1 a while ago. This means I have a spare Retail Win 7 Product Key which is not being used, so legally, I can install Win 10 on another system using the same, unused Win 7 key.

Presumably, it also means I could sell any of my old 'unwanted' Win 7 Retail Product Keys on eBay (??).

• Those of you who have a Product Key for Windows 7 Starter, Windows 7 Home Basic or Windows 7 Home Premium can upgrade to Windows 10 Home.
• Those of you who have a Windows 7 Professional or Windows 7 Ultimate Product Key can upgrade to Windows 10 Pro.

Note that this won't work with Windows 7 OEM Product Keys (the OEM licence is not transferable) and you cannot run two systems using the same Win 7 Retail Product Key (only one system will be activated).

Also, the free upgrade to Win 10 is only available for a year from the release date of Win 10, so this won't work after July 2016.

I have not actually tried this yet, and I wonder if anyone has? My guess is that on a clean install, Win 10 will 'phone home', see that the system hardware is different from the  hardware registered against that old Win7 key and refuse to activate it. However, unlike the OEM licence, the Retail Win 7 licence is transferable to another computer and so MS should allow you to upgrade to Win 10 using the Win 7 Retail licence on any system.

I suspect that you will have to install Win 7 using the Retail key, upgrade it to SP1 (if you did not install Win7 SP1) and then phone MS and ask for an activation code, after explaining that this is a new system. Once you have Win 7 activated, you can upgrade to Win 10 (either from a clean Win 10 install or by doing an in-place upgrade).

If anyone has first-hand experience on this subject, please let me know...