Microsoft has released a new Windows 7 beta to members of its TechNet and MSDN communities, and promised consumers they'll be able to get their hands on the software by the end of the week.

The release of the Windows 7 beta coincided with Microsoft CEO Steve Ballmer's keynote speech at the Consumer Electronics Show in Las Vegas on Wednesday night, where he told the audience that the code would be publicly available from Friday.

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The beta includes the promised interface tweaks that were not included in versions of Windows 7 handed to developers at the Professional Developers Conference in October.

The changes start with the Windows Taskbar, a core component of the Windows experience that has changed very little since it debuted in Windows 95. With Windows 7, it undergoes its biggest remodelling job ever: the familiar bars containing the name of running applications and tiny icons are gone, and in their place are unlabelled, jumbo icons that represent running apps.

windows 7 taskbar

Furthermore, while Windows 7's Taskbar still contains the Notification Area, also known as the System Tray, it's less crowded. The Notification Area in previous Windows versions tends to bulge at the seams with icons for applications that you don't remember installing and that often pester you with balloons alerting you to things you don't care about.

In the Windows 7 beta, Microsoft finally supplies tools to tackle this information overload. For each app, you can choose to display or hide its icon, and to show or suppress its notifications. The overflow area - where icons that don't fit in the Notification Area live - remains, but it's far less unwieldy: it now pops up, rather than shoving applications in the Taskbar to the left, and you can move icons between it and the Notification Area by dragging them from one place to the other.

In pictures: What's new in Windows 7?

Microsoft representatives speaking before Ballmer's keynote made a number of other promises about Windows 7's performance. For instance, it includes various power management tweaks designed to allow laptop users to get more time from their batteries. In previous Windows versions, unused ports - such as the Ethernet port - continue to drain power even when not in use. But given that a laptop connected wirelessly is unlikely to need the Ethernet port, there's no reason why the latter should be a battery hog. Windows 7 will manage that, and shut off power to unused ports.

Microsoft is also keen to explore the potential for allowing Windows 7 to support hardware 'sensors'. The company said laptop makers may in future choose to include motherboards with GPS sensors, allowing owners to use the machines as glorified satnavs. Another idea is to build light sensors into laptops, so screen brightness could automatically adjust to suit that lighting conditions. Microsoft plans to release APIs to companies interested in these and other sensor implementations so they'll work seamlessly with Windows 7.

Check back for more details of Microsoft's Windows 7 announcements at CES later today.