Bill Gates starred in a theatrical promotion of Window's Vista in New York City just hours before the home version of Microsoft's long-awaited new operating system made its debut.
Gates took to a stage in a grand and dramatically orchestrated Vista event before leaving for Europe where he was to begin a Vista-touting tour with stops in London, Edinburgh, Bucharest and Paris.
"With the digital lifestyle, people have very high expectations," Gates told an audience in a packed theater off Times Square in New York City.
"Windows, and now Vista, is the central element that allows the digital lifestyle to thrive."
Vista for home computers was slated to go on sale in the United States at midnight and worldwide at the first tick of clocks on Tuesday in time zones around the planet.
"It is a privilege to be here for the biggest launch in software history," Microsoft chief executive Steve Ballmer said after stepping on stage.
"We are incredibly excited about this product...We've really hit the ground running."
Vista will be available on Tuesday in 70 countries around the world, according to Ballmer.
Ballmer and Gates had a US family that helped test Vista come on stage and touch a "The Wow Starts Now" computer icon that signaled electronic billboards throughout Times Square to blaze with Vista advertisements.
The event was the beginning of what promises to be a flashy and expensive campaign by Microsoft to promote an operating system that took five years and six billion dollars to ready for the world.
Microsoft has heralded its long-awaited and oft-delayed Vista as its most sophisticated, secure and intuitive operating system since Windows was first rolled out to challenge Apple's Macintosh software in 1985.
The most obvious change in Vista is the new look. Vista's "Aero" interface uses 3-D graphics to create translucent windows that appear to float above the background screen.
Other changes are more subtle like improved security, search bars to help users find information easier and a new multimedia platform for digital video, music and pictures.
Reviews of Vista, which was put through extensive testing by computer makers and software developers, show it is packed with features that bring it up to date but break little new ground.
Apple calls Vista a copycat version of its Mac OS X Tiger operating system that introduced many of those new features. The iPod maker plans to introduce a new operating system of its own later this year.