BARCELONA - Microsoft on Wednesday officially unveiled the consumer preview of Windows 8, its next-generation operating system.

The updated OS preview is available now for download via preview.windows.com in English, French, German, Japanese, and simplified Chinese languages.

Microsoft unveiled the Windows 8 preview in Barcelona during Mobile World Congress, where Redmond is also pushing its Windows Phone platform. Windows chief Steven Sinofsky took to the stage at a press event here to talk up this "bold re-imagining of Windows."

"Our goal with Windows 8 is to deliver PCs without compromise," Sinofsky said, which means that the OS scales with you depending on how you want to use the OS and with what gadget - tablet, PC, or touch-based PC.

Windows 8 is "beautiful, modern, fast, and fluid," Sinofsky said, arguing that the new OS is a "generational change" in how Microsoft designed Windows. That last time that happened was with Windows 95 and back then, Redmond had to include a "click to start" button on the bottom left so people knew how to use it.

"At that time, computing was new to most Windows customers," Sinofsky said. "Today, computing has a huge number of distinct user models and interfaces, [but] Windows 8 [makes it] easy to use."

"We think it will be a super fun experience and will come natural to people," he continued.

Part of that experience is the Windows 8 app store. Microsoft unveiled a few of the new apps it selected to launch with the consumer preview, including PuzzleTouch Jigsaw, Air Soccer, Pew Pew, SigFig Portfolio, and Elements Weather. Sinofsky warned that they are all still a work in progress, but encouraged downloaders to play around with them.

Sinofsky also talked up the Windows 8 system-on-a-chip (SOC) architecture, which it detailed in a recent blog post. The company also demoed an Acer ultrabook that booted up in about eight seconds.

The consumer preview comes a few months after the Windows 8 developer preview launched at the BUILD conference in the fall. Since then, Sinofsky said, engineers have made more than 100,000 code changes to the OS for today's consumer preview.

When will the final version of Windows 8 be available? Sinofsky did not provide an exact timeline, though it's expected by year's end. He did say, however, that there will be updates to the OS and preview apps throughout the consumer preview period. He also promised more details on Windows 8 Enterprise at CeBIT. The next milestone for Windows 8 will be the release candidate, followed by release to manufacturing, and then general availability, he said.

At the close of his presentation, meanwhile, Sinofsky said the consumer preview had been downloaded by users in more than 70 countries in its first hour of availability.

For more, see PCMag's Hands On With Windows 8 Consumer Preview and the slideshow above. Also check out shots from today's event in the gallery below.