Microsoft Corp launched its new Windows 8 operating system and Surface tablet on Thursday in a bid to revive interest in its flagship product and regain ground lost to Apple Inc and Google Inc in mobile computing.
"We've re-imagined Windows and we've re-imagined the whole PC industry," Microsoft Chief Executive Steve Ballmer told Reuters Television.
Windows 8 devices and the company's new Surface tablet, which aims to challenge Apple's popular iPad head on, go on sale at midnight on Thursday.
Steven Sinofsky, head of Microsoft's Windows unit and the driving force behind Windows 8, opened the launch event in New York in front about 1,000 media and PC industry partners.
He showed off Windows 8's new touch-optimized design, but emphasized that the system was built upon the base of Windows 7, Microsoft's best-selling software that recently passed 670 million license sales.
While Windows 7 was introduced three years ago, Windows 8 represents the biggest change in Microsoft's user interface since Windows 95 came out 17 years ago.
The radical redesign, which dispenses with the Start button and features square tiles for apps, may surprise some users.
Initial demand for Windows 8 appeared solid, but customers were wary.
"We've seen steady pre-order sales on Windows 8 devices from early adopters," said Merle McIntosh, senior vice president of product management at online electronics retailer Newegg.
"However, we expect that most average consumers are waiting until after launch to make a purchase decision."