Microsoft’s Corporate Vice President of OEM Steven Guggenheimer shared an interesting nugget of information today during a keynote address at Computex: the company has sold more than 600 million licenses for Windows 7 in the three years it has been on the market. That’s up about 75 million since Microsoft’s last announcement in January of over 525 million licenses sold.

Windows 7 is currently the operating system on nearly 40% of internet connected devices, according to Microsoft figures. Although that’s still behind Windows XP’s estimated 45% of the market, the trend is clear and it doesn’t seem like the forthcoming release of Windows 8 is slowing sales in the meantime.

In contrast, Windows Vista has faced a rapid decline over the past couple of years going from around 15% in July 2010 to less than 7% today, according to figures gathered by NetApplications.

Now that Microsoft’s focus is shifting towards Windows 8, the company will face a significant challenge introducing the changes that come with the new OS, including the revamped Metro user interface and its touch oriented design. Only time will tell if it’ll be a smooth transition for consumers and businesses.

This is “the biggest launch time in Microsoft's history,” according to Guggenheimer. “In addition to updating Windows client, Windows Server, phone and embedded platforms, there's a massive wave of software and services coming to market, from Windows Azure, to Office 15, Xbox games, Skype and Bing."

The company also showed off the video above which highlights the evolution of Windows 7 devices.