Additionally, we will see how to install another product key instead. In this article, we will see how to deactivate Windows 10 by uninstalling the product key. Deactivation is also useful if you want to use your product key on some other PC and stop using it on the current PC. If you are about to sell or give away your PC but want to keep Windows 10 installed there, it is a good idea to deactivate it. Advertisement Activation verifies that your copy of Windows is not used on more devices than the license allows.