Steve Ballmer took to the stage Thursday to formally introduce the world to Windows 7, Microsoft's newest operating system and best hope for erasing memories of the failed product known as Vista.

Windows 7 screen shot
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Ballmer said Windows 7 is simple to use, responsive, and politely secure—all things that Vista was not.

The OS "makes everyday use of a PC better," said Ballmer, speaking before several hundred customers, analysts, and members of the media in New York City.

"I'm Steve Ballmer, and I'm a Windows 7 PC, effective immediately," said the CEO, paraphrasing a recent Windows promotional campaign.

Ballmer said Microsoft worked with 3,000 engineers and 50,000 tech industry partners to build a product that he hopes will eventually make its way to 8 million customers. To get Windows 7 right, Ballmer said Microsoft engineers constructed a "wishing wall," on which they white-boarded the emotional, technical, and visual attributes the software required to be a success.

"Windows needs to be an incredible opportunity for innovation," said Ballmer, who insisted that Windows 7's speed and agility would be immediately apparent to consumers. "You want that computer to boot up quickly? Boom!" said Ballmer, who added the OS is "less busy" than its predecessor.

Computer users knocked Windows Vista for its intrusive security features, heavy horsepower requirements, and incompatibility with many older software programs. To boost compatibility in Windows 7, Microsoft added to some versions an "XP mode" that emulates Vista's predecessor, which is still in use by most businesses.

Windows 7 also provides native support for new input modes, such as touch-screen computing. Windows 7 hit online shops like Amazon and electronics retailers, including Best Buy, early Thursday.

Microsoft needs the product to be a hit, as Windows sales have slumped badly in recent quarters. The fall of is partly due to the economy and partly as a result of Vista's unpopularity and inability to run on smaller devices such as netbooks. Given its smaller footprint, Windows 7 fits nicely on most netbooks, according to Microsoft.

The full version of Windows 7 Professional is $299, with upgrades going for $199. Windows 7 Ultimate is priced at $319, with the upgrade version at $219. The full version of Windows 7 Home Premium is priced at $199, with an upgrade from Vista or XP costing $119.

InformationWeek has published an indepth report on Windows 7. Download the report here (registration required).