Microsoft revamps Office

It makes use of cloud computing by storing documents and settings on the Internet by default, and is compatible with touch screens widely used in tablets. It as well incorporates Skype, the video-calling service Microsoft bought for $8.5 billion in 2011.

The latest version of Office comes as Apple Inc

The latest version of Office comes as Apple Inc and Google Inc make inroads into the workplace, long Microsoft's stronghold. Office is Microsoft's single-biggest profit driver.

Microsoft has a lot riding on the 15th version of Office. Windows is one of the world's biggest computing platforms, and the Office applications - Word, Excel, PowerPoint, and other tools - are used by more than 1 billion people around the world.

Growing trend toward providing software

Cloud computing refers to a growing trend toward providing software, storage and other services from remote data centers over the Web instead of relying on software or data installed on individual PCs.

Documents in the sleeker-looking Office can be marked up by writing on a touch screen with a stylus. The suite will be compatible with tablets that use Windows 8 - due for release in October.

Microsoft did not say whether it planned to launch versions of Office compatible with Apple's iPad or tablets running Google's Android platform.

“The Windows 8 launch is right around the corner, and we have a lot to do ... To a certain extent, it feels to us a lot like 1995,” Ballmer said, referring to Microsoft's Windows 95 operating system which was a significant step forward at that time.

The most exciting

“We have the most exciting, vibrant version of Windows in years,” Ballmer said. He did not disclose pricing plans for the new Office.

Google has been pushing hard to persuade Office users to switch to Google Docs, an applications suite running on Google's servers and accessible on the cloud and mobile devices. Apple has as well been trumpeting the ability of its iPad - the dominant tablet in the market today - to perform clerical duties.

“This puts them even farther ahead of Apple in terms of product richness. Nevertheless it however leaves the door open to competition from Google pursuing a strategy that's cross-device, cross-platform - and is free,” said Sarah Rotman Epps, an analyst at Forrester.