The US Supreme Court has cleared the way for Novell to proceed with its multi-billion antitrust case against Microsoft, which it accuses of unfairly undermining its WordPerfect word processor.

The US judges yesterday refused Microsoft's request to reject a lower court decision that ruled Novell can proceed with its case. Microsoft had argued the judges shoudl reject the case as Novell did not compete in the operating system market.

Novell suit charges Microsoft with withholding vital technical information that it needed to make its WordPerfect program run smoothly on Microsoft's Windows operating system.

Novell says Microsoft officials knew that withholding the information would damage WordPerfect and that it was a deliberate strategy to emasculate the competition.

According to Novell, the value of WordPerfect fell from $1.2bn in May 1994 to just $170m in 1996, when it was sold to Corel. In 1990 WordPerfect had a 50% share of the word processing market; by 1996 it was just 10%.

Microsoft has argued that it was Novell's own mismanagement that was responsible for WordPerfect's decline.

"We believe the facts will show that Novell's claims, which are 12 to 14 years old, are without merit," Microsoft said in a statement.

Microsoft has already paid other competitors billions to settle unrelated antitrust suits.