Speaking at an event to launch Windows Phone 8, a new operating system for smartphones, Ballmer said the new computer operating system was greeted with enthusiasm at its launch on Friday.

"We're seeing preliminary demand well above where we were with Windows 7, which is gratifying," he said. "We're seeing retailers here in the United States and hardware manufacturers enthusiastic about the response."

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When Windows 8 went on sale Friday, there were lines at Microsoft Stores across the U.S., although many of those waiting said they were more interested in Surface, a Microsoft-developed tablet computer that went on sale the same day. Windows 8 is available both in stores and through online download.

The new OS brings touch to the desktop operating system.