At the Start screen, swipe in from the right side, or hover your mouse in the upper-right corner of the screen to display the charms menu.
Tap or click the Settings charm.
Tap or click Change PC Settings.
Tap or click Activate Windows.
If your computer is not activated, PC Settings provides instructions that are customized to your activation error. If telephone support can provide help resolve your error, tap or click the appropriate link, that may resemble one of the following:
Activate
Activate by phone
Contact customer support for help