Your Windows 10 product key serves as proof that you actually own Windows 10, and might need to be entered when you reinstall ...

Windows 10 has reached end of life, but you can continue using it by enrolling your PC into the ESU program for free.

Lost your Windows 7 product key? Use this quick guide to recover it from stickers, emails, tools, or Microsoft Support.

Don't want to fork over $30 to keep getting Windows 10 security updates? Microsoft is offering a couple of ways to avoid the fee, but customers in Europe get the best deal.