US computing giant Microsoft on Tuesday gave  the key Chinese market an early peek at its new tablet computer and Windows 8  software, promising a “fast and fluid” operating system. Microsoft will launch Windows 8 and the Surface tablet computer, designed  to compete with Apple’s popular iPad, in the United States on Friday. The launch of the two products in China is the same day. Windows remains the dominant platform for personal computers, but it has lost ground to Apple and Google in newer devices which use rival operating  systems. “With Windows 8, we introduced this fast and fluid experience that works  across a broad range of different types of PCs (personal computers),” said  Steven Sinofsky, president of Microsoft’s Windows division. “Windows 8 seamlessly moves between a world of touch-only tablets to  laptops that have touch screens to desktops and to portable computers without  touch screens,” he said in a speech to the media in Shanghai. Microsoft’s new tablet computer was designed to be a platform for Windows, Sinofsky said, as he compared the challenger to Apple’s iPad. “Even though it’s bigger than an iPad, it’s actually lighter in your hand  because of the way the physics of the design work,” he said. The Surface has a full-sized USB port unlike the iPad, a built-in stand and  a cover which doubles as a keyboard, he said. It runs the new Windows RT, a form of Windows 8, and comes with Microsoft  Office 2013. It is not Microsoft’s first foray into the tablet market. In 2000 the company unveiled a prototype tablet PC and shortly afterwards began licensing  its specifications to various manufacturers. An analyst said Microsoft’s tablet would battle for market share in China,  which has the world’s largest number of Internet users at more than 500 million. “It doesn’t have a price advantage over the iPad, so consumers who can  afford a tablet may still be inclined to choose Apple’s iPad,” said Gerry Xu,  of global information company IHS. Some who have tested Windows 8 complain about the change from earlier  versions of Windows, which could force users to relearn how to operate their  computers, the New York Times reported on Sunday.