Speculation is building that Microsoft will unveil a tablet computer on Monday.
The company was secretive when it invited media to an afternoon event in Los Angeles, saying it would be a "major" announcement and would not divulge the location until Monday morning.
In an email, the company had said, "This will be a major Microsoft announcement - you will not want to miss it."
Several media outlets, including The New York Times, cited unnamed sources saying that Microsoft will launch its own tablet to boost its new Windows 8 operating system and counter Apple's hot-selling iPad.
Microsoft declined to comment.
Microsoft is preparing to release its new operating system, Windows 8, which works across laptop computers, tablets and even televisions.