Microsoft Windows was a fact of life for an entire generation raised on the PC. But we live in a different world now, and perhaps nothing underscores how much that world has changed more than the fact that the version of Windows that Microsoft is getting ready to launch this year is its most important product launch in decades.

It has been 17 years since the general public was genuinely excited by a new version of Windows: people actually lined up to buy Windows 95 like it was the iPhone or something. Years of meandering followed: Windows ME was a joke, Windows XP was an updated but essentially similar experience to Windows 95, Windows Vista was an attempt to correct XP’s security issues but turned into a joke of its own, and Windows 7 was what Vista should have been yet failed to inspire. In the meantime, Apple and Google captured the attention of software developers and the public with mobile computers built around iOS and Android.

But Windows 8 is going to be different. Tomorrow morning in Barcelona (at a telecom industry conference, of all things) Microsoft is going to unveil the Consumer Preview Edition of Windows 8, and if it arrives on schedule and without incident later this year, it could accelerate the world’s transition toward a mobile-first vision of general purpose computing.

Windows 8 is a huge development for Microsoft in several ways:

• The Windows user experience has been radically overhauled with the Metro user interface, which has been a critically acclaimed (if not revenue-generating) part of the Windows Phone design. Metro will be unfamiliar to the millions raised on the concept of the “Start” button (now the Windows logo button on Windows 7) in the lower left-hand corner of the screen, but it allows Microsoft to embrace a new era of computing that is more and more about the touch screen.
• Microsoft developed a version of Windows 8 for ARM processors, a chip brand unfamiliar to most average computer users but which is at the heart of nearly every single smartphone and tablet sold over the last several years. Even though Intel seems to have finally gotten its act together in the power-sensitive mobile space, ARM is an industry standard for mobile processing and will allow PC companies like HP to build power-efficient tablets in hopes of competing with the iPad.
• Microsoft has always had a big problem: introducing radical new changes in Windows breaks a lot of business applications that were built for previous versions, which has led the company to move slowly through transitional periods. Windows 8 represents one of the biggest leaps forward for mainstream Windows developers in what seems like forever, but Microsoft had no choice but to include a “Desktop” user interface version of Windows 8 that will run old applications. The transition between Metro and Desktop could be jarring, and conservative support for Metro may not expose as many Windows 8 users as possible to the best parts of Windows 8.
• Applications written for the Metro user interface will be sold through the Windows Store, as opposed to the more traditional shrink-wrapped or downloadable software sold for Windows. Sharing revenue with Microsoft will be a new experience for the Windows development community, although it’s established practice for iOS developers and Microsoft will actually take a smaller cut than Apple once an app’s revenue passes $25,000.

The traditional PC isn’t going anywhere just yet, but just ask HP and Dell: nor is it in good shape. Wednesday could be the first day when we realize whether or not Windows 8 can be a product that allows the traditional PC industry to refocus itself around both traditional PCs in lighter forms as well as iPad competitors.

The stakes for Microsoft are enormous. The company largely subsists on two cash cows: Windows and Office, and Windows sales are under pressure with the slow decline of the PC market.

But there’s also an existential crisis at hand for Microsoft. It defined personal computing in the years after Apple lost its way in the 1980s, and now that Apple is very much back in that role Microsoft desperately wants to remind the world that it is capable of setting a new bar for personal computing.

After getting a few glimpses of Windows 8, the tech industry started wondering if Microsoft has finally come up with something unique. Come Wednesday, when enthusiasts can begin to put the software through the paces, we’ll start to get a better idea of whether Microsoft is ready for a new era.

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• Tablet market to hit over 377 million units by 2016
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• Tablet market to hit over 377 million units by 2016