What happens when the activation period runs out?
Actually there is no activation period, microsoft nuked it.
Microsoft has ditched the 30-day grace period, a trademark of Windows 7, in the retail copies of Windows 8, mandating that users provide a product key during setup.
After installing, you must go online and activate your PC, you had 30 days before, not now.
http://www.computerworld.com/s/article/9230399/Microsoft_ends_activation_grace_period_with_Windows_8