Microsoft Corp is revamping its search engine to counter the dominance of Google Inc in the web search and related advertising business.

The world's largest software company, which is still in talks with Yahoo Inc over a potential partnership, has long been determined to play a major role in the lucrative Web search market after watching upstart Google take a stranglehold.

Microsoft, which has been testing the search engine internally under the name Kumo for several months, plans to introduce the new service, re-christened Bing, over the next few days, with a full launch next Wednesday.

Advertising Age reported earlier this week that Microsoft was planning a $80 million to $100 million ad campaign to promote Bing. Microsoft declined comment on the report.

The Redmond, Washington-based firm has lots of ground to make up. Last month Google took 64.2 percent of U.S. Internet searches -- up half a percentage point from the month before -- handling 9.5 billion out of a total of 14.8 billion searches.

Yahoo was a distant second with 20.4 percent of searches and Microsoft third with 8.2 percent, both down slightly from the month before, according to data firm comScore.

Both Google and Yahoo have recently introduced new features in their search engines to attract users, making Microsoft's task even harder.

(Reporting by Bill Rigby; Editing by Derek Caney)