There may only be a few more days in the life of Napster.

The digital-music swapping service, which had the music industry quaking in its boots and college students spending even more time at their computers, will have only three business days to block the trading of copyrighted songs designated by the music industry, a federal judge ruled Tuesday. 

"It brings us closer and closer to the brass ring," Howard King, attorney for Metallica and Dr. Dre, told FOXNews.com by telephone Tuesday afternoon. "And that (goal) is that our client's music would not be available on Napster." 

King heads up Metallica and Dr. Dre's $10 million suits against Napster. 

That means that as soon as record labels hand Napster a list of no-no songs, the service that changed the face of both music and the Internet has exactly three days to shut down a critical portion of what it does. 

It also means that the estimated 55 million who use the service to get free computer-file copies of everything from Corelli to Etta James to Dr. Dre will have to find their tunes elsewhere. 

If Napster does not comply, the song-swapping service that has drawn more than 50 million free-music fans could be held in contempt of court. 

"I think Napster will surely make an attempt to comply," said Phil Leigh, an analyst with Raymond James & Associates. "I think you have the self-preservation instinct at work here." 

Hilary Rosen, president of the Record Industry Association of America, said the record labels would comply fully with the court's order. 

"We are gratified the District Court acted so promptly in issuing its injunction requiring Napster to remove infringing works from its system," she said. "We intend to provide the notifications prescribed by the Court expeditiously, and look forward to the end of Napster's infringing activity." 

King said the question now is whether Napster will live up to the ruling. 

"It's technologically doable," he said. "The question is, is Napster going to go to the necessary steps to do it?" 

After Tuesday's stinging defeat, Napster had nothing to say immediately. 

"We won't have a comment at this time," Napster spokeswoman Tobey Dorschel said Tuesday. 

But in a statement released Friday after a San Francisco court hearing before U.S. District Judge Marilyn Hall Patel, Napster CEO Hank Barry insisted that the record labels should be cutting a deal with his company, not trying to shut it down. So far, the labels haven't touched a $1 billion settlement offer from Napster. 

"This is a case that should be settled," Barry said in the statement. "We must come up with a solution that works for consumers and pays artists. Let us never lose sight that the members of the Napster community are the world's most passionate music fans and the industry's best customers." 

King said his clients were not offered part of the $1 billion settlement, but that mention was made of a licensing deal. 

"My clients have not been interested in having their music available on Napster at any price," he said. "As for a licensing deal, our clients aren't interest in participating." 

Tuesday's ruling was a modified version of one issued earlier by Patel. Her earlier injunction was struck down last month as too broad by the 9th U.S. Circuit Court of Appeals. 

The new injunction orders the record companies involved in the suit to make a list of the copyrighted songs they want blocked from the site, the name of the artist for each song and the name of the computer-file version of each song. 

By shifting some of the burden of protecting copyrighted songs to the labels, Patel brought the injunction in line with the appellate court's ruling. Acknowledging that there might be difficulties complying with the order, or that something as simple as a changed filename could cause headaches, Patel said she would appoint a technical expert to the case if necessary. 

Apparently, Patel wasn't satisfied with a screening system Napster began using this weekend, which would have weeded out 1 million files of copyrighted music. 

Napster offered the system during Friday's hearing in the hopes it would mollify the record labels, which claim that by promoting the pirating of material, Napster could potentially cost billions of dollars worth of lost revenue. But the system was imperfect, blocking access to some copyrighted songs by artists while allowing users to copy other equally protected songs by the same bands. 

By Friday's hearing, it seemed an accepted fact that Napster would no longer deal with copyrighted songs. Instead, the argument was more about who was responsible for doing the work in deciding what should and shouldn't be barred. 

Music industry attorney Russell Frackman told Patel that Napster should start blocking access to songs listed on Billboard's Top 100 singles and Top 200 albums charts, and by policing its system to keep those lists current. 

Napster attorney David Boies said the burden should be on the record labels to find infringing MP3 files on Napster and then make notice of those files to the company. 

But although Napster had painted an injunction in the direst terms — flatly stating that one would be a virtual death sentence — Eric Scheirer, an analyst with Forrester Research, said Tuesday's injunction doesn't mean the last of the service. 

"The record industry has the advantage now of being able to get these songs off Napster any time they choose," Scheirer added. "But if they do it now, consumers will flee to all these other alternative services where they won't be able to control them." 

Meanwhile, users flocked to Napster for last minute downloads and also swamped alternatives services like Gnutella and Napster clones. 

A program called Napigator directed hundred of thousands of music fans to servers located around the world that can be tapped into using the Napster application. 

On Monday, more than 96 million music files were traded by more than half a million people through computer servers located as far away as Italy, New Zealand and Russia — numbers that rivaled Napster itself even as downloads peaked this weekend. 

King said a victory against Napster would create the legal precedents that would help labels and artists shut down those services as well. He said his clients hadn't yet decided whether to pursue Gnutella or other Napster clones. 

Napster itself joined forces with German music giant Bertelsmann AG and is gearing up to become a subscription-based service,. It seems inevitable that the era of free Internet music is over — at least for that Redwood City, Ca., company. 

All parties are due to meet with a mediator on Friday.