Windows 8 and 8.1 PCs no longer have a Certificate of Authenticity (CoA) sticker with their product key printed on it. This helps prevent theft — people can’t just glance at a sticker on your laptop to get your Windows product key. On the other hand, you can’t simply look at a sticker on your Windows PC when you reinstall the operating system. You’ll have to find the 25-digit product key elsewhere.
Having your product key is necessary if you want to download Windows 8 or 8.1 installation media from Microsoft. Their downloads require a valid product key. It’s also useful if you want to perform a fresh install of Windows to wipe away all the bloatware that comes with a new PC.
Embedded in UEFI Firmware
PCs that come with Windows 8, Windows 8.1, and Windows RT have an encrypted product key embedded in their UEFI firmware. When you reinstall the same version of Windows 8 or 8.1 on a PC that came with it, the product key will be automatically applied and activated. You won’t see any product key prompt — it will all happen automatically.
This only applies if you’re installing the same copy of Windows. This doesn’t apply if you install an upgrade copy, a system-builder copy, or a different edition of Windows 8. This also won’t work if you try to install Windows 8.1 on a PC that came with Windows 8 — Windows 8.1 and Windows 8 have different product keys for some reason, so you’d need to install the original version of Windows 8 and then upgrade to Windows 8.1 via the Windows Store.
This feature is designed to simplify things, but you may need to get at your Windows product key anyway — use a tool in the next section to view this hidden key while Windows is installed.
On a Running Windows System
The Windows product key is normally hidden and not shown anywhere in Windows’ interface. However, you can use a third-party utility to view the product key stored in Windows. You can then write down this product key and re-enter it when installing Windows. This is the only way to find the Windows product key on PCs that come with Windows 8 or 8.1 pre-installed.
You’ll need to download a third-party tool for this. We like NirSoft’s lightweight ProduKey utility, but you can also use another product-key-finding utility. Run the tool and it will display the Windows product key in use on your current Windows system — write it down so you can use it later.
In a Purchase Confirmation Email
If you purchased Windows 8 or Windows 8.1 online — maybe you grabbed that cheap $40 or $15 offer when Windows 8 was released — you’ll find your Windows 8 or 8.1 product key included in an email Microsoft sent you at the time of purchase. The product key from this email can be used when you reinstall Windows 8 or 8.1.
Here’s what our email looks like. Its subject is “Thanks for ordering Windows 8″ and it was sent from Microsoft Customer Support. Your email may look a bit different if you purchased Windows 8 or 8.1 more recently.
Included In a Retail Windows Box
If you purchased a retail, boxed copy of Windows 8 or Windows 8.1, you’ll find your product key included on a card in that box. You may need to dig the box out of your closet to find your product key. Look for a card with a picture of a key on it. If you set it aside when you originally installed Windows 8, we hope you remember where you put it!
Visit Microsoft’s Upgrade Windows with only a product key page to download installation media for Windows 8 or 8.1 — all you need is the product key you found above.
Having trouble? Bear in mind that Windows 8 and Windows 8.1 have different product keys for some reason. If you have a Windows 8 key, you can’t install Windows 8.1 — you have to install Windows 8 and use the free upgrade to Windows 8.1. If you have a Windows 8.1 key, you can’t install Windows 8 with it. If you try either of these things, you’ll receive an “invalid product key” message. Windows 8.1 is a free upgrade to all Windows 8 users, so why Microsoft decided to make this so complicated is a mystery.