New York, Oct. 25 (Reuters): Microsoft Corp launched its new Windows 8 operating system and Surface tablet today 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 reimagined Windows and we’ve reimagined the whole PC industry,” Microsoft chief executive Steve Ballmer told Reuters early today ahead of the launch.

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 today.

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 look, but stressed that the system was built upon the base of Windows 7, Microsoft’s best-selling software that recently passed 670 million licence sales.

The new design of Windows, which dispenses with the Start button and features square tiles for apps, may surprise some users. Initial demand appeared solid, but customers were wary.

Early reviews of the Surface tablet were mixed, with praise for its slick hardware, but concerns about battery life and limited software and applications available.

“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.”