Microsoft chief exec Steve Ballmer skirted rumours that Windows Vista will be the last operating system from the software giant, claiming that Microsoft has "plenty more where that came from" at a press event to mark the consumer launch of the new OS.

Sitting alongside execs from some of Microsoft's most important partners - Intel, HP and Dell among others - Ballmer said there remains lots of room for innovation on the PC, and that Microsoft planned to continue to build upon the user-interface, security and multimedia enhancements in Vista.

"We've got a very long list of stuff our engineers want to do, a long list of stuff all of the companies here want us to do," he said. "There are so many areas where we need innovation."

However, Ballmer was hesitant to talk much about what comes after Vista, dodging a question about if and when customers will see the first service pack for Vista. "We'll put one out if we need to," he said.

Ballmer was his usual boisterous self but there was a subdued air in the room at Cipriani, where press and analysts gathered for the first of two Vista events in New York. Five years in the making and plagued by several delays, Vista has been a constant subject of scrutiny for some time, making the release an somewhat of an anti-climax.

Ballmer predicted Vista would be adopted five times faster than Windows 95 and twice as fast as Windows XP in the next three months, and called the opportunity for partners to drive value for customers with Vista "huge". Although even he noted that most of the units of Vista will be pre-installed on hardware, and sales of the packaged OS will be considerably less.

New York's festivities - which included an evening presentation by Ballmer and chairman Bill Gates followed by a launch reception - were just two of several launch events around the globe.