Microsoft's attempt to win a new trial in a patent-infringement case has resulted in a bigger fine for the software giant.

A Texan judge slapped an additional $25 million in "enhanced damages" on Microsoft for "litigation misconduct," in its case against z4 Technologies brought in September 2004.

Judge Leonard Davis said that Microsoft tried to have z4's patents declared unenforceable even as it continued to willfully infringe on those patents and withheld evidence of its actions. He ruled that this misconduct merits adding to the amount of damages Microsoft must pay z4 in the case.

Davis also denied motions by both Microsoft and co-defendant Autodesk to schedule a new trial, after a ruling in April that they must pay z4 millions of dollars for infringing on two of the company's patents.

The Texas court awarded z4, a private company founded by David Colvin and based in Commerce Township, Michigan, $115 million from Microsoft and $18 million from Autodesk to settle a patent-infringement suit.

In addition to the added $25 million fine levied against Microsoft, the company also must pay z4's $1.98 million in lawyer's fees. A judge also ordered Autodesk to pay $322,000 in attorney's fees to z4 and also upheld the company's original fine.

The verdict in the case in April found that both Microsoft and Autodesk infringed on patents 6,044,471 and 6,785,825. The patents are for product-activation technology aimed at preventing unauthorised use or piracy of software.

Both Autodesk and Microsoft continue to contend that neither company infringed on z4's patents.

Autodesk spokeswoman Caroline Kawashima said the company is "very disappointed" and plans to appeal the decision. "We believe that the facts in this case clearly show that Autodesk and others developed their own product activation technologies well before z4 Technologies claims to have created this technology," she said. Microsoft also plans to appeal the court's decision.