“I am a devoted Apple fan — I was in line for the iPhone,” said Axel Roesler, assistant professor for interaction design at the University of Washington in Seattle, but Windows Phone “strikes me as quite different and an advance.”

Windows Phone, which began appearing in devices in fall 2010, certainly stands out visually. It has bold, on-screen typography and a mosaic of animated tiles on the home screen — a stark departure from the neat grid of icons made popular by the iPhone. While most phones force users to open stand-alone apps to get into social networks, Facebook and Twitter are wired into Windows Phone. The tiles spring to life as friends or family post fresh pictures, text messages and status updates.

Even so, relatively few consumers have been tempted, and sales have been lackluster. A big problem is that, initially, the handsets running Microsoft’s software, made by companies like HTC and Samsung, were unexceptional. Even more important, wireless carriers, the gatekeepers for nearly all mobile phones, have not been aggressively selling Windows phones in their stores. Most promote the iPhone and devices running Google’s Android operating system.

And so Microsoft has struck a partnership with Nokia, and executives at both companies have high hopes that their handsets will catch on with consumers. On Monday at the International Consumer Electronics Show in Las Vegas, Nokia plans to introduce a sleek metallic Windows Phone called the Lumia 900 that will be sold by AT&T in the United States, according to two people with knowledge of its plans who spoke on condition of anonymity because the product has not yet been announced. Unlike other handset makers creating devices with Microsoft’s software, Nokia is not also developing Android phones.

“We are doing our best work for Windows Phone,” said Stephen Elop, the chief executive of Nokia and a former Microsoft executive.