The European Commission has agreed to launch another monopoly investigation into Microsoft after further allegations that it is abusing its market position.

The investigation will go ahead following a complaint from Norwegian-based web browser company Opera in December that the US software giant makes it too hard for rivals to its Internet Explorer software to run on its ubiquitous operating system.

The claim is backed by an industry group - the European Committee for Interoperable Systems (ECIS) - which includes IBM, Nokia and Oracle.

In September, the European Commission upheld a landmark ruling from 2004 that Microsoft illegally bundled audiovisual software into Windows, and imposed a fine of €778m (£589m).