Less than three months after it pulled out of the joint venture that owned MSNBC.com, Microsoft Corp. (Nasdaq: MSFT) is launching its own news operation.

The world’s largest software maker, which in July sold its 50 percent stake in MSNBC.com to NBCUniversal, will launch a news service along with its Windows 8 operating system later this month. According to Reuters, Bob Visse, the general manager of MSN Product Management Group, said Microsoft is making a "big, multi-million dollar investment" to create a “decent-sized media operation.”

The news operation will be part of Microsoft’s major overhaul for MSN, which will primarily aggregate news stories from services such as Reuters (NYSE: TRI) the Associated Press and NBC, now a unit of Comcast Corp. (Nasdaq: CMCSA). The company will also produce original news content, but it is unclear how much.  

The MSN portal attracts some 480 million visitors per month worldwide, and 123 million from the United States. It is among the largest Web portals in the world, along with Yahoo (Nasdaq: YHOO) and AOL (NYSE: AOL). The site’s redesign will be touch-optimized for Microsoft’s Windows 8/Windows RT and Internet Explorer 10, all of which will be available on Oct. 26.

The company is showing a preview of the new portal in New York this week as part of Advertising Week. The updated MSN portal will be available only for Windows 8/Windows RT and Internet Explorer 10 users.  

Microsoft pulled out of its joint operation with MSNBC.com after a 16-year relationship, which began to go south in 2005 when the software company sold its stake in MSNBC’s cable channel to NBC. As time went on, Microsoft execs became increasingly frustrated by contractual terms that required it to feature its content exclusively on MSNBC.com

MSNBC.com is currently winding down its newsroom at Microsoft’s campus in Redmond., Wash., near Seattle. The website now redirects users to NBCnews.com.

Microsoft’s new news operation will employ staffers in Redmond as well as New York. According to Reuters, Visse did not say how many journalists the news operation will employ.