Microsoft CEO Steve Ballmer can't afford to be wrong about Windows 8.
Thursday in New York, Microsoft unveiled a dramatic overhaul of its ubiquitous Windows operating system. It goes on sale Friday, fused into more than 1,000 PCs and other devices. If it flops, the failure will reinforce perceptions that Microsoft is falling behind competitors such as Apple, Google and Amazon as its stranglehold on personal computers becomes less relevant in an era of smartphones, tablets and other mobile devices.
If Ballmer is right, Windows 8 will prove that the world's largest software maker still has the technological chops and marketing muscle to shape the future of computing.
"This is going to be his defining moment," said technology industry analyst Patrick Moorhead of Moor Insights & Strategy. Ballmer's "legacy will be looked at as what he did or didn't do with Windows 8."
The new system is designed to run on PCs and tablet computers, heralding the biggest change to the industry's dominant operating system in at least 17 years. It also marks the first time that Microsoft has made touch-screen control the top priority, though the system can still be switched into the familiar desktop mode that allows for control by keyboard and mouse.
Ballmer sees Windows 8 as the catalyst for a new era at Microsoft. He wants the operating system to ensure the company plays an integral role on all the important screens in people's lives -- PCs, smartphones, tablets and televisions.
"You are going to love the new Windows," Ballmer promised during Thursday's presentation. At other points of his speech, Ballmer hailed the new PCs running on the "bold, innovative" system as the best ever made.
Early reaction has been mixed. Some reviewers like the way the system greets users with a mosaic of tiles displaying applications instead of relying on the desktop icons that served as the welcome mat for years. Critics say it's a confusing jumble that will frustrate users accustomed to the older versions, particularly when they switch to desktop mode and don't see the familiar "start" button and menu.
Windows 8 hits the market backed by an estimated $1-billion marketing campaign, a measure of how important it is to Microsoft's future.
Ballmer's margin for error is slim after being consistently outpaced by Apple and Google in his nearly 13 years as CEO. During his tenure, Microsoft's stock has lost nearly half its value, wiping out more than $200 billion in shareholder wealth.