CHRONOLOGY-Steve Ballmer's tenure as Microsoft CEO-
SAN FRANCISCO, Aug 23 (Reuters) - Microsoft Corp CEO Steve Ballmer unexpectedly announced on Friday that he would retire in 2014, 13 years after he took over the dominant personal computer software company and tried to steer it into growing markets like video games, portable music players, smartphones and tablets.
The following is a chronology of events during Ballmer's time as Microsoft chief executive.
1998 - Ballmer assumes role of president at Microsoft and takes charge of day-to-day operations. Prior to that, he led numerous divisions, including sales and support and operating-systems development.
2000 - Ballmer succeeds Microsoft co-founder Bill Gates as CEO in January. The two met as students at Harvard University, where Gates lived down the hall from Ballmer. In 1975, 19-year-old Gates dropped out of Harvard and went on to found Microsoft along with Paul Allen.
2001 - In November, Microsoft enters the gaming market with the North American release of its Xbox gaming console, competing with game consoles from Nintendo Co Ltd and Sony Corp. .
2005 - Microsoft launches the next-generation Xbox 360 video game console in November, strengthening its foothold in the video game hardware market.
2006 - Microsoft launches Zune portable music player in November. It is the first Microsoft-designed device to compete in a market dominated by Apple Inc's iPod. The music player does not gain enough of a market, and Microsoft discontinues selling it by mid-2012.
2007 - In January, Microsoft unveils the Windows Vista, which becomes the company's least popular operating system.
2008 -- Ballmer makes an unsolicited $44.6 billion, $31-per-share, cash-and-stock takeover offer to Yahoo Inc's board. Yahoo rejects the bid as too low.
2009 - Microsoft revamps its search engine to counter Google Inc's dominance in the Web search and related advertising business. In May, Ballmer reveals the new search engine, dubbed "Bing" that is set for a June release.
2009 -- In July, Microsoft and Yahoo launch a 10-year Web search deal to challenge market leader Google. Under the deal, the two companies agree that Microsoft's Bing search engine will power search queries on Yahoo's sites. They have been in on-again, off-again talks since Yahoo rebuffed Microsoft's takeover bid.
2010 - Microsoft releases its Windows Phone operating system for mobile phones, trying to claw its way into the smartphone market and woo consumers away from Apple's iPhone and Google's Andriod devices.
2011 - In February, Nokia and Microsoft strike a deal, in a bid to take on the smartphone market. By 2013, the partnership has yet to produce a product that has taken market share from Google and Apple.
2012 - Microsoft, hoping for a hit, launches Surface tablets and its Windows 8 operating system that uses touch commands. The devices do not gain much market share in the tablet market, dominated by Apple's iPad and Samsung's Galaxy mobile devices.
2013 - On August 23, Ballmer announces he will step down within 12 months, surprising industry watchers.