Microsoft says it has now sold 180 million Vista licences.

(It did not report how many of those licences may have been "downgraded" to Windows XP by corporate users.)

The Windows Vista operating system has been plagued with glitches and incompatibilities, and many Windows XP users are refusing to upgrade to the OS.

The news came when Microsoft's CFO Chris Liddel announced that the company has topped US$60 billion in yearly revenue for the first time in its history.