LOS ANGELES -- Microsoft Corp. gave the first extensive public demonstration of the next release of its Windows operating system as it seeks to avoid some of the stumbles that occurred with the last version, Windows Vista.

At a technical conference here, the Redmond, Wash., company also provided programmers with a test version of the software, dubbed Windows 7. The move is an important step to drum up support among independent developers.

Microsoft said it would also further embrace a growing shift towards online software by making a future Web-based version of its Office suite of productivity applications available free. It is a move to counter efforts by Google Inc. and others to encroach on Microsoft's turf with free word processing, spreadsheet and other programs.

Microsoft's Windows Vista received a critical drubbing when it was released nearly two years ago. Vista was criticized for the sluggish performance of the software and initial incompatibilities with digital cameras and some other devices. Microsoft says the incompatibilities have largely been corrected with updates to Windows Vista.

At the same time, Windows Vista endured attacks from rival Apple Inc. in a long-running advertising campaign for Apple's Macintosh computers. Microsoft recently began an ad campaign for Windows, partly to correct the negative perception of the software.