Asked about this, Reller said that Windows 8 has been meeting Microsoft's sales expectations all along, and that the high level of demand specifically for touch devices with the new OS has "surprised a lot of people."

Unfortunately, that caused an initial shortage of such devices. "Frankly, the supply was too short," she said at the event, which was held at the CES show in Las Vegas and where she answered questions from a JP Morgan analyst.

There were other distribution issues. "There was some misalignment between where products were distributed and where the demand was," she said.