Wel,microsoft r giving all win8.1 preview users a free winblue pro upgrade..u can install winblue pro via windows upgrade,all u need 2 do is get connected,go 2 windows store and by this time store has already discovered u as a candidate 4 the free iso upgrade...click "install microsoft_windows8.1 pro" n there u go,however,learn to be patient the full software is about 3gb and may take upto 2 days to finish......what i find most fascinating about win8.1 pro is the ability 2 automatically back-up windows updates,thanks to the in-built skydrive integration.