After a two-month trial, Novell's $1.3 billion antitrust lawsuit against Microsoft ended in a hung jury, according to a spokesman for Microsoft who was at the court.

"It is confirmed that the jury could not come to an accord and that no length of further deliberation would alter that," said the spokesman, who is with one of Microsoft's public relations agencies.

The jury had been deliberating for almost three days after closing arguments were presented earlier this week.

Microsoft and The Attachmate Group, which is the parent company of Novell, could not immediately be reached for comment.

The jury had asked for clarification on several points during deliberations, including questions about the definition of "middleware." The terminology apparently caused some confusion. At one point, the jury asked whether Windows 95 was considered "an operating system or middleware," court filings show.

Novell filed its antitrust lawsuit seven years ago, claiming Microsoft abused its dominant position in the PC OS market to harm Novell's desktop applications business.

Novell accused Microsoft of misleading it about certain technical details prior to the release of Windows 95, to the detriment of Novell's WordPerfect, Quattro Pro and other applications. Microsoft's behaviour ran afoul of US antitrust laws, according to Novell, which was seeking approximately $1.3 billion in damages.

Last month, former Microsoft CEO Bill Gates took the stand and denied his company had acted in a way to deliberately harm Novell. The changes to Windows 95 were required to make the OS stable, he told the jury. Novell could have produced more compatible versions of its software but acted too slowly, Gates said.