"To put that in context, more 10% of all PCs worldwide are already running Windows 7 today," said Brandon LeBlanc, Microsoft's in-house Windows blogger, in a post.
For the quarter, Windows sales were up 28% year-over-year, to $4.4 billion.
Still, Microsoft's Windows XP, now almost a decade old, remains the most popular OS. It's currently on 64.5% of PCs, according to data from market watcher Net Applications. Windows Vista holds a 10.2% share.
Overall, Microsoft said earnings per share for the period increased 36%, year-over-year, to 45 cents. Net income climbed 35%, to $4.01 billion, on record revenue of $14.5 billion, a 6% gain from the year ago quarter.
Wall Street analysts surveyed by Thomson First Call were, on average, expecting Microsoft to report quarterly EPS of 42 cents, and income of $4.8 billion on revenue of $14.4 billion.
Microsoft's results were mixed across its other product lines.
Sales in its Server and Tools division increased 2.4%, to $3.6 billion.
Revenue from the company's Business unit was off 6%, to $4.2 billion, as customers remained on the sidelines in anticipation of the arrival of Office 2010, which is set for release in June. In addition to the standard versions of Word, Excel, PowerPoint, and OneNote, Office 2010 also includes free access to Web-based editions of the apps.
Sales in Microsoft's Online Services unit were up 12%, to $566 million, while revenue from the company's Entertainment & Devices group, which is home to the Xbox and Windows Games products, rose 2.2%, to $1.7 billion.
Microsoft shares were off 1.82%, to $30.82, in mid-afternoon trading Friday.