Yes, you can reuse it

Can you upgrade from Windows 7 to Windows 10 for free? Here’s the answer.

Is it still possible to upgrade to Windows 10 with a Windows 7 product key? Best answer: Yes, but proceed with caution, and here’s why.

Windows 10 activated using a Windows 7 product key in 2019

The end of support for Windows 7 will happen on January 14, 2020, which means that after that day, Microsoft will stop offering support, including security and improvement updates, as well as phone support.

If you’re still running Windows 7, it’s recommended to upgrade to Windows 10 as soon as possible to continue receiving support. Although the Windows 10 offer to upgrade for free is over, you can still upgrade to Windows 10 using the Windows 7 product key.

As of the time of this writing, performing a clean installation of Windows 10, and using a legitimate Windows 7 (retail) license in the Activation settings page is confirmed to activate successfully. However, you should proceed with caution, because Microsoft no longer offers free upgrades, as such the company can stop devices from activating using this method at any time.

In the event that the product key doesn’t work, or you don’t have a legitimate license, the upgrade from Windows 7 to Windows 10 will cost you $139 to move to the Home edition or starting at $150 to jump to the Pro edition.

If you need help, you can use these instructions to upgrade from Windows 7 to Windows 10 without losing your files ,or you can use these instructions to upgrade using a clean installation of Windows 10.