The US technology giant said the "far-reaching realignment" would help integrate efforts around its software and devices.
"We are rallying behind a single strategy as one company -- not a collection of divisional strategies," chief executive Steve Ballmer said in a memo to employees.
"Although we will deliver multiple devices and services to execute and monetise the strategy, the single core strategy will drive us to set shared goals for everything we do. We will see our product line holistically, not as a set of islands."
"Today's announcement will enable us to execute even better on our strategy to deliver a family of devices and services that best empower people for the activities they value most and the enterprise extensions and services that are most valuable to business," he said.
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Microsoft remains the dominant PC software firm with its Windows operating system but its activities have broadened with the Xbox gaming console, the Windows Phone operating system and the Surface tablet. The company also offers cloud and business services.
"Building upon Windows, Xbox and our growing suite of consumer and enterprise services, we will design, create and deliver through us and through third parties a complete family of Windows-powered devices -- devices that can help people just as much in their work life as they do after hours," Ballmer said.
"We will strive for a single experience for everything in a person's life that matters. One experience, one company, one set of learnings, one set of apps, and one personal library of entertainment, photos and information everywhere. One store for everything."
A research note from Citi analysts earlier today said investors "have significantly underestimated the company's ability to maintain/grow its revenue in core franchises of Windows, Server and Tools and Business Division.