KMSPico

KMSpico is a software tool that can be used to activate (license) multiple versions of Microsoft Windows and Office. It requires no keygen or cracking, and it does this by emulating a real KMS (Key Management Service) server on the local computer and forcing installed Windows and Office products to self-activate against it.

KMS activation is completely safe and legal (for testing purposes) and ensures that your software remains activated for 180 days.
Thereafter, the KMSPico service running in the background on your PC will automatically reactivate your Microsoft products for 180 days, essentially ensuring that your Windows and Office installations never expire.