WASHINGTON, Nov. 30 (Xinhua) -- Microsoft launched Windows Vista, the long-awaited update to the software giant's ubiquitous operating system, for business customers on Thursday.

    The company also announced new versions of its Office software suite and Exchange Server messaging system, CNN reported.

    "This is the biggest launch in our company's history," said Microsoft Chief Executive Officer Steve Ballmer, noting that Vista and Office 2007 are the most significant releases for the company's flagship products.

    The launch of Vista has been delayed for several times, and consumers, unlike business customers, will be unable to get their hands on a copy of the software until the end of January, 2007.

    Microsoft contends that Vista will make computers more secure, powerful and graphically dynamic especially when combined with other products Microsoft is releasing simultaneously.

    The most noticeable changes in Vista involve three-dimensional graphics and much better search capabilities, but the software also incorporates huge changes behind the scenes.

    Programs have less access to the core of the operating system, closing a vulnerability that malicious hackers have giddily exploited in the past. Vista also includes basic anti-virus software.

    Analysts expect the roll out of the first update to the Windows operating system in five years, along with the new version of Office, to drive Microsoft's revenue in 2007.

    IT market research firm IDC expects Microsoft to ship some 90 million units of Vista next year. Individual consumers are expected to lead the uptake of the new system, while corporate users will probably wait longer to upgrade, IDC said.

    Microsoft estimates that more than 200 million people will be using at least one of its newly launched products by the end of next year.