It’s hard to believe that Windows 8 has been available for two months now. If one of your PCs is still running a release preview build that was made available before the official release date of October 26th, then you have until January 15th to decide to upgrade fully before your preview version expires.
All three preview builds including the Windows 8 Developer, Consumer and Release versions will expire on January 15th. After the passage of this expiry date, Windows 8 will send a message to the user that it will begin restarting Windows every hour until an activation key is entered or you revert to a previous install of Windows. Ouch. Additionally, if you received a new Windows 7 laptop for Christmas, you’re eligible for Microsoft’s $15 upgrade option here.