New York ? Microsoft Corp. knows the cell phone world is where it’s happening, and it’s determined to be a part of it.

After years of declining sales of phones based on Microsoft’s Windows Mobile software, the company is starting with a fresh slate — a completely new operating system for phones.

The new handsets will go up against Apple Inc.’s highly popular iPhone and the expanding number of phones running on Google Inc.’s Android operating system.

The first phone with Windows Phone 7 will be the Samsung Focus, which hits AT&T Inc. stores Nov. 8 for $200 with a two-year contract requirement, Micro-soft said Monday. It will be closely followed by two more phones for AT&T, made by LG Electronics Inc. and HTC Corp., and one for T-Mobile USA, also made by HTC.

In May, Microsoft launched another new phone software package, Kin, only to yank it about two months later in the face of dismal sales. Windows Phone 7 is a different beast, and Microsoft is putting its full weight behind it.

In all, Microsoft an-nounced nine phones for the U.S. market on Monday, including one from Dell Inc., and it has lined up 60 carriers in 30 countries to carry Windows 7 phones.

Another U.S. carrier, Sprint Nextel Corp., is getting Windows 7 phones in the first half of next year.

In the most recent quarter, Microsoft’s older system, Windows Mobile, accounted for just 5 percent of the worldwide smart phone market.

From a hardware standpoint, the Windows 7 phones are indistinguishable from high-end Android phones: They have big touch screens, and a few models have slide-out keyboards.

To stand out from the competition, Microsoft has given the software a different look. It is centered on “tiles” on the front screen that are supposed to tell the user at a glance about important new information, such as e-mail and Facebook status update.