Microsoft has launched its latest bid to be computer users' default window on to the web, BBC reports.

The firm has released a beta, or test, version of its latest web browser, Internet Explorer 9 (IE9), which it hopes will help revive its fortunes in an increasingly competitive market.

Since 2003, the company has seen a 97% lead in market share dwindle to 60%.

IE9 will compete with new versions of other popular browsers such as Mozilla's Firefox and Google's Chrome.

Google Chrome now commands more than 7.5% of the market, despite only being first released in December 2008.

Mozilla, which has recently launched a test version of Firefox 4, has nearly a quarter of the market and in some countries is the dominant web browser.

Many browsers received a boost when the European Commission forced Microsoft to offer users of its Windows operating system a choice of browser, rather than Internet Explorer as a default.

Ina Fried, who covers Microsoft for technology site CNet, said the new software brought Microsoft "back in serious browser contention".

"Internet Explorer still dominates in market share, but they have been losing out for years to Firefox and more recently Chrome mainly because of where they were on the technology front," she told BBC News.