New York ? Acrobatics, blaring music and plenty of hype accompanied Microsoft Corp.’s long-delayed debut of its new Windows Vista operating system.

Hours before the software went on sale in New York, dancers clad in Microsoft colors dangled from ropes high above street level Monday and unfurled flags to form the red, green, blue and yellow Windows logo against a building wall.

Later, two explosively loud, percussion-heavy rock bands riled up Microsoft enthusiasts amid flashing lights at the Nokia Theatre – temporarily renamed the Windows Vista Theatre – in Times Square. As employees at Microsoft’s Redmond, Wash., headquarters watched live video feeds, company-colored balloons dropped from the ceiling, a few wielding prizes.

Vista was set to go on sale in 70 countries today, along with new versions of Microsoft Exchange e-mail software and the flagship Office business suite, which includes Word, Excel and PowerPoint. Several retailers had even scheduled midnight openings.

But unlike the recent launches of next-generation game machines like Sony Corp.’s PlayStation 3, customers haven’t been camping out for days.

“When I look at Windows Vista, I see a technology that is interesting, that is relevant, but to some extent is evolutionary,” said Al Gillen, an analyst at the technology research group IDC. “I do not believe it will create a lot of motivation for people to rush out and get a new operating system.”

In an interview, Microsoft chairman Bill Gates said the company wasn’t pushing midnight sales events – after all, consumers can download it over the Web for the first time. Even that route will be relatively rarely taken – CEO Steve Ballmer told one audience that, as in the past, most consumers will switch to Vista only when they buy new computers.

More than five years in the making, Vista was released for businesses Nov. 30, but the unveiling for consumers only came today. Vista retails for $100 to $400, depending on the version and whether the user is upgrading from Windows XP.

Microsoft contends that Vista is such a huge improvement over previous computing platforms that users inevitably say “Wow” when they see it. Gates ticked off some examples, such as how Vista presents a slick 3-D graphical user interface and document icons that give at-a-glance previews.

Vista comes as changing dynamics of computing – notably the rise of open-source software and Web-based services that replicate what traditionally could be done only on a desktop computer – are threatening Microsoft’s dominance in the industry.

But Gates contended that the operating system has a higher profile than ever before, as the PC has morphed from a souped-up typewriter to a networked entertainment center, personal media library and gateway to the Internet.

“When people think about their PC, they think about Windows even more than who the manufacturer is,” Gates told The Associated Press. “That determines how it looks, how you navigate, what the applications are that are available.”

And in this case, Vista has folded in programs that users once bought separately – including automated backup systems and some spyware protections.

Microsoft built Vista so that different layers could be upgraded separately, so it’s possible that this is the last massive, all-in-one update for Windows. No matter how Microsoft chooses to roll out Vista’s successor, Ballmer said there’s still work to be done.

“Developers need a richer platform if we’re going to get speech, voice, natural language, and more rich 3-D-type graphics into the user interface,” Ballmer said. Plus, the technologies around the PC – chips, storage, high-definition DVD will all evolve, he said. “The operating system will need to evolve with them.”