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.

UAC did this through pop-up windows, which also were spoofed by Apple in television ads because Vista users reported they appeared so frequently, even when users were performing authorized tasks.

Sinofsky acknowledged that Microsoft "went a little too far with UAC," but as a result the Windows client OS is now more secure. In Windows 7, Microsoft will focus on the security aspects of UAC but will ensure it is not an invasive feature for users, he said.

During Tuesday's keynote, Microsoft showed off some new features in Windows 7, including a streamlined view of all the files and folders contained not only on a user's PC, but also any other PCs on networks that the users are allowed access to.

This feature is called Libraries, and it will improve desktop search in Windows 7 by allowing users to search more comprehensively across PC folders than ever before, according to Microsoft.

Microsoft also changed its Gadgets feature, another new Vista feature. Gadgets are mini-applications that give users quick access to information, such as stock prices or weather, with icons that users in Windows 7 will be able to move around the desktop. In Vista, gadget icons were confined to a task bar.

Perhaps the sexiest new Windows 7 feature demonstrated Tuesday was its touchscreen interface, which lets people use their fingertips and small hand gestures to control applications on their PCs.

Microsoft demonstrated how touchscreen controls can replace the mouse for things like opening the taskbar and choosing a Windows Explorer window. If a user opens a folder with photos in it in Windows Folder, they can scroll through those photos using their fingers, and drag a photo into a Windows Paint application window and draw directly on the photo.