Microsoft's Windows 10 event is just getting started, and it sounds like the company is eager to make it as easy and cheap as possible for those running older versions of Windows to upgrade. Terry Myerson just announced on stage that, for the first year after Windows 10 launches, any device running Windows 7, Windows 8.1, or Windows Phone 8.1 will be able to upgrade to the latest version of MIcrosoft's OS — for free. How exactly this program will work isn't clear just yet — it'll certainly be subject to some hardware requirements, particularly for older machines running Windows 7. But a simplified upgrade path will likely do a lot to help Windows 10 adoption — rather than dealing with a number of different versions of Windows and different upgrade costs, most consumers will simply take this free update and enjoy running Microsoft's latest.