A Windows 10 product key is a 25-character code formatted like this: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX . It’s divided into five groups of five alphanumeric characters.

If your PC is already activated with a Digital License, you will see a message saying “Windows is activated with a digital license.” You do not need to enter a key.

If you don’t have a key, you cannot simply “generate” one. Algorithmic key generators are scams filled with malware. Here are the legal, safe ways to acquire a key:

The key is blocked or already used on another PC. Fix: If you are reinstalling on a new motherboard, you must buy a new key. If you are reinstalling on the same PC, use the “Troubleshoot” button in Activation settings and select “I changed hardware on this device recently.”

This occurs when a valid license isn't found for your PC. Ensure you typed the key correctly or run the Activation Troubleshooter found in Settings > Update & Security > Activation.

There is zero performance difference between activated and unactivated Windows 10. Your games, apps, and internet speed are unaffected.