To activate Windows legally, you can use a digital license that’s linked to your Microsoft account, enter a 25-character product key you bought from Microsoft or an authorized reseller, or—if you’re in an organization—use volume licensing managed by your IT team. Open Settings → Activation (or Update & Security → Activation on older Windows), then either sign in with the Microsoft account that holds your digital license or click Change product key and enter the key. If activation fails after a hardware change, use the Activation troubleshooter and the “I changed hardware on this device” option to reactivate via your Microsoft account.

Microsoft Office activates either by signing in with the Microsoft account tied to a Microsoft 365 subscription or by entering a product key for one-time purchases (Office 2019/2021). Open any Office app, go to File → Account (or Office Account), and sign in to automatically activate if your subscription is linked. For product-key installs you can use office.com/setup or the change product key option inside older Office versions. Business editions use volume licensing (KMS/MAK) handled by IT. You can also download kmspico to activate windows and office

If activation repeatedly fails, sign out and sign back in, run the built-in troubleshooters, or contact Microsoft Support for help. Avoid unofficial activators or “cracks”: they violate Microsoft’s license, often carry malware, and can break updates or support. If cost is a concern, use Office for the web (free at office.com) or free alternatives like LibreOffice.