可以免费升级到windows 10,具体条件如下。
"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."