Microsoft's forthcoming Windows Vista will crack down on software pirates by greatly reducing the functionality of a stolen version of the operating system. 

The anti-piracy feature is part of the new Software Protection Platform that Microsoft unveiled earlier today.

It will be applied to several of the vendor's software products, beginning with Windows Vista and the forthcoming Windows Longhorn Server.

After installation users have 30 days to enter a product key for the software. If the key is not entered, the system will run in a so-called " reduced functionality" mode.

The system will not offer a start-up menu or desktop icons and the background will change to black. Users will be able to activate the web browser and access the internet for up to one hour, at which point they will be automatically logged out.

This situation will also occur when users enter a stolen registration key. The operating system has a way to detect whether the activation system is hacked to bypass the product activation feature, but will respond in a different way.

Vista will lock out the user from several of the software's advanced features such as the new Windows Aero user interface, Windows Defender security features and the Readyboost technology that offers to increase system performance through the use of USB memory keys.

Unlicensed copies will still have access to critical security updates. Microsoft also stressed that it will not disable the computers of users with pirated Vista versions.

The Software Protection Platform instead aims to create a gap between the functionalities of genuine and pirated software, thereby creating an incentive to purchase the legal and fully functioning version.

The Software Protection Platform replaces the Windows Genuine Advantage technology first launched in July 2005.

The feature determines whether a system runs an authorised copy of Windows when it attempt to access Microsoft download services such as Windows Update and Microsoft Download Center. Unlicensed systems are denied access.

Hackers have successfully cracked the feature and instructions on how to disable the validation checks are widely available on the internet.

Windows Vista is scheduled for consumer availability in January 2007. Windows Longhorn Server has been promised for the second half of 2007.