The report is good news for Microsoft, which has taken its licks lately in the mobile computing market. Redmond's but Windows Phone 7 OS has yet to catch on among consumers, who are like crazy.

Windows 7 has proven a big hit on the desktop, however: 42 percent of PCs worldwide will run Win 7 by the end of 2011, Gartner reports. And nearly 635 million new PCs are expected to ship with the OS by the end of the year.

After a slow start, corporations are finally migrating from Windows XP to Windows 7. "Many enterprises have been planning their deployment of Windows 7 for the last 12 to 18 months, and are now moving rapidly to Windows 7," said Gartner research director Annette Jump in a statement.

However, Windows 7 will likely be the last version of Microsoft's iconic OS that gets deployed via massive, enterprise-wide migrations. The move toward virtual and cloud computing architectures in the next five years will change how upcoming versions of Windows are deployed, the study says.

Another long-term issue for Windows is the rise of "OS-agnostic" applications for both consumer and enterprise PCs. As early as next year, half of enterprise apps won't be tied to any particular operating system. In the consumer market, the proportion of OS-agnostic apps already exceeds Windows-specific apps, Gartner estimates.