Windows remains functional without activation, but you'll be locked out of personalization and other non-essential features until it's addressed.

Your Windows 10 product key may be necessary to unlock all features -- but it's not easy to find. Here's where to look for the product key (even if it's lost).

Fix Error 0xC004C003, 0xC004C003, The activation server determined the specified product key is blocked, on Windows 11/10, by following this guide.

On Windows 11, you can check the activation status in three ways through the Settings app, Command Prompt (or PowerShell), and the Run command, and in this guide, I will teach you how.

Product key and activation with Windows 10 free upgrade: When you upgrade your PC to Windows 10 from Windows 8 or 7, your licence will be tied to the hardware upgrade, not to the Microsoft account.

Successfully fix The product key you entered didn't work, Error 0x80041023 during Windows Activation on Windows 11/10 computers.