To get started open the Settings app and go to System > About.
Click on Change product key or upgrade your edition of Windows.
That will open the Settings > Update & Security > Activation page.
Click on Change product keyand accept the subsequent UAC prompt.
This new window will pop up and you just enter your current Windows 7 or 8 product key.
As soon as the entire sequence is entered the system will immediately go online to validate the product key.
Product key being validated.
Once the product key is validated you will need to click Next to finish the activation process.
Once activation is successful just click Close and your system is now activated directly using your Windows 7/8 product key.
