How to upgrade an old PC to Windows 10 - free
Microsoft's new activation rules for Windows 10 take some getting used to.
The biggest change is in the way product keys are handled for so-called "digital entitlements." If you take advantage of Microsoft's offer of a free upgrade from Windows 7 or Windows 8.1 to Windows 10, you don't need a Windows 10 product key at all.
Instead, a digital fingerprint of your hardware is stored on Microsoft's activation servers, allowing you to reinstall that edition of Windows on that hardware without the need for a product key.
In addition, beginning with the November 2015 update to Windows 10, aka version 1511, you can use Windows 7, Windows 8, or Windows 8.1 product keys to activate your installation of Windows 10.
And to further complicate things, Microsoft supplies default product keys for Windows 10 that can be used to unlock an edition without activating it. I've already seen one article from one notoriously sensational and invariably inaccurate source that claims this allows "free upgrades" to Windows 10 Pro.
No, it doesn't.
But the new rules do enable some interesting scenarios, especially where edition upgrades, such as moving from Windows 10 Home to Pro, are concerned.
In particular, it means that old product keys you might have lying around are suddenly worthwhile. For example, Microsoft sold heavily discounted upgrades to Windows 8 Pro in the first few months after launch. In addition, you might have retail copies of Windows 7 Professional or Ultimate available, where the license associated with their product key is no longer in use.
Those keys can be reused to enable an upgrade from Windows 10 Home to Windows 10 Pro, potentially saving you $100.
I've been testing upgrade/activation scenarios on a wide variety of hardware recently to see how things work. Here's the scoop.
SCENARIO 1: CLEAN REINSTALL
I recently upgraded the SSD in an HP Spectre x360 that originally shipped with Windows 8.1 Home and had then been upgraded to Windows 10 Pro. After the upgrade was complete, I used a USB flash drive to reinstall a clean copy of Windows 10 Pro.
Twice during the installation process, I was prompted to enter a product key. Both times I chose the option to skip entering the key.
When setup was complete, I signed in and checked the activation status (Settings, Update & Security, Activation). The system was properly activated, because Microsoft's servers recognized the hardware and used the digital entitlement.
SCENARIO 2: CLEAN REINSTALL, WITH EDITION UPGRADE
As part of my testing, I used a Surface 3 that originally shipped with Windows 8.1 Home and had been upgraded to Windows 10 using a digital entitlement. It had then been upgraded from Home to Pro using a Windows 10 product key from MSDN. So this device actually was registered with digital entitlements for both versions of Windows 10 (Home and Pro) on Microsoft's activation servers.
I then downloaded Microsoft's recovery image for the Surface 3, copied it to a USB flash drive, and reinstalled the original operating system, Windows 8.1 Home.
Next, I used Windows Update to upgrade this system to Windows 10. That worked fine, with one problem: My new installation of Windows 10 was for the Home edition. But I have a digital entitlement to Windows 10 Pro. How do I force that upgrade?
That's where the default product key comes in. I clicked Change Product Key from the System Control Panel (there's an identical button on the Activation page in Settings). That opens this dialog box.
I then entered the default Windows 10 Pro product key:
That signaled to Windows that I wanted to upgrade from Home to Pro, as shown here.
I clicked Start Upgrade, and after a few minutes, the system restarted. As soon as I connected to the Internet, the Windows activation process checked my hardware against Microsoft's servers. Because this hardware was already recorded with a digital entitlement to Windows 10 Pro, I was activated immediately, without the need to enter a product key.
SCENARIO 3: UPGRADING A NEW PC FROM HOME TO PRO
Let's say you buy a new PC with Windows 10 Home installed by the OEM. When you check the Activation page in Settings, it should look something like this:
If you have a Windows 10 Pro product key, you can click the Change Product Key button and enter it here. Easy.
If you don't have a Pro product key and you want to buy one, you can click Go To Store and purchase the upgrade for $100. Also easy.
But what if you have a Windows 7 Professional or Ultimate key, or a Windows 8/8.1 Pro key? In that case, you need to do the upgrade in two steps.
First, make sure you've installed the November update and you are running version 1511.
Next, click Change Product Key and enter the default Windows 10 Pro key (see above). After the upgrade completes, check the Activation screen again and you'll see this:
What, you were expecting that default key to magically give you a $100 upgrade? Sorry, that's not how it works, despite what you might have read elsewhere.
Instead, click the Change Product Key button and enter your Windows 7 Pro/Ultimate or Windows 8/8.1 Pro key. Assuming it's a legitimate key and you are running Windows 10 version 1511 or later, your activation should complete successfully.
If that process seems cumbersome, you're right. It does go fairly quickly, however.