Microsoft on Tuesday for the first time publicly demonstrated Windows 7, the next major release of its OS for PCs that Microsoft insists will reflect lessons learned from the widely panned Windows Vista.

Microsoft also laid out a road map for the release of Windows 7 and handed out a pre-beta version to developers at the Professional Developers Conference (PDC), where it also demonstrated new features in a keynote address Tuesday.

The first public beta of the OS will be available early next year, and subsequent test releases and release candidates will follow based on that feedback, said Steven Sinofsky, senior vice president of Windows and Windows Live at Microsoft.

Windows 7 is still targeted for release three years after Vista, he added. This would put its business release in late 2009 and general availability at the end of January 2010 if the OS remains on schedule.

In his keynote Tuesday, Sinofsky said Microsoft is learning its lessons from Vista, which was widely criticized by users and the press, and spoofed famously in humorous television advertisements by competitor Apple.

Sinofsky acknowledged that some of the criticism was deserved, particularly around Microsoft's lack of preparing its hardware, software and peripheral partners for Vista's release, even though it was more than five years in the making.

Early Vista users experienced incompatibility with applications and found that devices and peripherals would not work with the OS because drivers weren't available upon the release of the OS.

Microsoft won't repeat this mistake with Vista, Sinofsky said, and because the OS kernel -- or its underlying code base -- is the same as the one in Vista and Windows Server 2008, all of the devices and applications that work with those OSes should also run on Windows 7.

"All of this device and compatibility work will pay off in Windows 7," he said.

Microsoft also will tweak the User Account Control feature (UAC), which was new in Vista, so it will be less of an inconvenience and work more efficiently for users, Sinofsky said.

UAC prevents users without administrative privileges from making unauthorized changes to a PC. But because of how it was set up in Vista, it can prevent even authorized users on the network from being able to access applications and features they should normally have access to.

The IDG News Service is a Network World affiliate.