If you’re reinstalling Windows 7 on a computer that had it pre-installed by the manufacturer, the key on the Certificate of Authenticity (COA) sticker is an OEM key that can only be used with that specific manufacturer’s version of Windows 7. It won’t work for a retail installation or with a different manufacturer’s recovery media.
The product key you have may be for a different edition of Windows 7 than the one you’re trying to activate. For example, a Home Premium key won’t work with a Professional installation.
If you’re getting an error that the key “does not match the current Windows SKU”, it means the key is for a different edition.
Windows 7 product keys can no longer be used to activate Windows 10 or 11. Microsoft stopped accepting 7 and 8 keys for 10/11 activation at some point.
As of July 29, 2016, the free Windows 10 upgrade offer expired. However, many found they could still upgrade without needing to buy a new key, as 10 and 11 use the same licenses. But 7 and 8 keys no longer work for activating 10 or 11.
If you have a valid retail or volume license key for Windows 7, you can still use it to activate a fresh installation of Windows 7. But if the key is tied to a specific manufacturer, you’ll need to use their recovery media or contact them for a replacement key.
What to Do If Your Windows 7 Key No Longer Works
If you have a valid retail or volume license key, you can try these steps to activate Windows 7:
Reinstall Windows 7 using the same edition as before (e.g. Home Premium, Professional, etc.)
Enter your product key when prompted during setup
If that doesn’t work, use the “Change product key” feature in System Properties to enter the key again
If you have an OEM key that came with a pre-built PC, contact the manufacturer for assistance. They may be able to provide a valid key or recovery media to reinstall Windows 7 properly.
As an alternative, you could consider upgrading to Windows 10 or 11. While 7 keys no longer work for activation, you may be able to use a valid 10 key to activate a fresh installation of 10 or 11.