Microsoft founder Bill Gates said on Tuesday the company's Windows Vista operating system had been incredibly well received.

"People who sell PCs have seen a very nice lift in their sales. People have come in and wanted to buy Vista," Gates told reporters at an Ottawa news conference.

Gates made the comments when asked to clarify last week's comments by Microsoft Chief Executive Steve Ballmer that analysts' forecasts for fiscal 2008 revenue for the Windows Vista operating system were "overly aggressive."

Microsoft, the world's largest software maker, released Vista, the upgrade to its ubiquitous Windows operating system, nearly three weeks ago and predicted that consumers would move to Vista faster than they did to past Windows upgrades.

The Windows franchise is the centerpiece of Microsoft's business because the company makes more than 75 cents in operating profit for every dollar of sales.

Asked by Reuters if there was anything that would make Microsoft cautious about the outlook for Vista, Gates replied: "I don't know what you mean. Vista's had an incredible reception.