The dispute dates back to December 2001 when Microsoft filed a trade mark suit seeking to prevent Lindows Inc, the company behind the Linux-based operating system Lindows, from using the terms LindowsOS and Lindows.com, arguing that they infringe on its rights in Windows.
In February, District Judge Coughenour ruled that the meaning of the term 'windows' should be considered not in its current day usage, but in the usage common at the time before Microsoft's Windows products were released onto the market – the period 1983 to 1985.
Crucially, if 'windows' is found to be generic term, it cannot be the basis for a trade mark.
The Court also ruled that once a word is declared generic it continues to be generic, meaning that no amount of subsequent marketing around a generic word changes the generic state of the word.
The ruling is fundamental to Microsoft's case and so Judge Coughenour allowed an appeal on the issue before the full case goes to trial. It is this appeal that has now been denied and the trial, which was originally scheduled to begin on 1st March, looks likely to take place in the second half of the year.
"We're looking forward to getting this trial back on the fast track and presenting our piles of evidence – videos, magazines, internal Microsoft documents – which clearly shows the generic use of 'windows' before Microsoft commandeered the word," said Michael Robertson, CEO of Lindows.
"This outright denial of Microsoft's appeal confirms that the trial will focus on how consumers and the software industry used the term 'windows' in the 1980s, before Microsoft dominated the landscape," he added.
"The court of appeals decision clearly moves up the timeline in this process, but we are confident in our case and prepared to go to trial," Microsoft spokeswoman Stacy Drake told CNET News.com. "This is an important trade mark principle and one we are prepared to vigorously defend in court."
Lindows recently announced that it was changing its product name to Linspire to avoid the risk of being taken to court by Microsoft in every country in which it tries to do business. Microsoft had succeeded in obtaining injunctions against the company in Finland, Sweden and the Benelux countries.