Microsoft said Friday that its new Windows 7 computer operating system will include a tool that allows users to upgrade from a basic version of the OS to one of its more feature-rich cousins at the touch of a button.

Windows 7 screen shot
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"While we know a majority of our customers will purchase their preferred SKU preinstalled on their PC, we do recognize there are scenarios where users may want to quickly and easily upgrade to a different version of Windows 7," a Microsoft spokesperson said.

Through the program, which Microsoft is calling Windows Anytime Upgrade, users can launch a screen from within Windows 7 that lets them purchase a product key for a pricier version of the software. Users can also enter a product key for an upgrade previously purchased at retail.

After purchasing or entering the product key, buyers can upgrade to whichever version of Windows 7 they choose with just a few clicks.

Consumers can upgrade from Windows 7 Starter to Windows 7 Home Premium for $79.99. Moving from Windows 7 Home Premium to Windows 7 Professional costs $89.99. Home Premium to Windows 7 Ultimate is priced at $139.99.

Microsoft officials said Windows Anytime Upgrade could appeal to consumers under a number of scenarios. "A customer may purchase a netbook thinking they would use it primarily for e-mail," said Brandon LeBlanc, Microsoft's in-house Windows blogger, in a post Friday. "Over time, they find they are using that netbook as their primary everyday PC," wrote LeBlanc.

"WAU makes it super easy to upgrade to Windows 7 Home Premium," LeBlanc added.

The program could help Microsoft's battered top line, as it would allow the company to extract additional client revenue from its installed base of Windows customers. WAU could also help the software maker sell more premium versions of Windows.

Microsoft cited an unfavorable mix of basic-to-premium sales as a factor when it reported that Windows sales plunged 29% in the most recent quarter. Windows 7 has been released to computer makers and will be available to the general public on Oct. 22nd.

Upgrading from XP to Windows 7? Here's a step-by-step guide.