TOKYO, Nov. 5, 2009 (Kyodo News International) -- Visiting Microsoft (NASDAQ:MSFT) Corp. Chief Executive Officer Steve Ballmer on Thursday offered an upbeat assessment of Japan's response to Microsoft's newly launched Windows 7 operating system, saying there has been a ''great response'' in the world's second-largest economy.

''Certainly we've seen initial sales be fantastic,'' Ballmer said in a news conference in Tokyo, noting that around 230 major firms have decided to install the OS that was launched Oct. 22.

''The first 10 days were bigger than the first 10 days of XP or Vista,'' he added, in reference to Windows 7's predecessors.

Microsoft is presenting Windows 7 as a faster and lighter operating system, following its highly unpopular predecessor Windows Vista that debuted in 2007 and suffered from slow speeds, frequent crashes and complicated security functions, analysts said.

As a result, many firms and consumers continued using Windows XP, which was released in 2001.

''Windows 7 is an example of the kind of innovations that I think are important in the technology marketplace,'' Ballmer said, stressing that Microsoft's long-term goal is to enhance its capacity for innovation and boost performance especially amid the current global economic downturn.

Ballmer said he is ''quite pleased'' with Microsoft's Japanese unit, its top performing subsidiary, and noted that Microsoft will be working with Japanese research institutions to conduct joint research on the future of computing.

The Microsoft CEO stressed the vital role of cloud computing in the company's growth.

Cloud computing allows users to access software over the Internet rather than installing it on their computers.

While Ballmer conceded that U.S. search engine giant Google Inc., Microsoft's main rival in cloud computing, is the leader in online search, he said Microsoft is leading the pack in other fields such as instant messaging.