I bought the above referenced machine 1.5 months ago. Every label on it advertised 64Bit O/S and it definitely didn't give me any option to do anything else when I first started it. Initially I was a bit nervous but 6 weeks into it I LOVE it. It's fast, the display is beautiful, It can run as many apps as I can throw at it all together and not slow down at all. Vista has its quirks that I've become used to. Now when I sit at an XP box it really feels OLD. I wouldn't go back for anything.