This type of computer arcana is usually of no interest to people who don't read PC World, but in this case your attention is required.

Your computer might be infected, and the culprit's not some anarchistic computer geek but one of the most powerful entertainment companies around: Sony BMG.

In November, Sony admitted to putting rootkits on 52 CD titles ranging from the new Our Lady Peace to Pete Seeger's Greatest Hits, ostensibly to protect the music by tracking whenever the discs were played on a computer and ensuring they were never burned as MP3s.

They have the power, however, to send information about your computer's internal world out into the swirl of cyberspace.

The rootkits were discovered by computer programmer Mark Russinovich on October 31 and (appropriately) revealed to the world through a scathing article on his blog ( www.sysinternals.com ). Sony initially defended its action by parroting the oft-repeated claim that the music industry is a victim struggling against an epidemic of piracy.

In following weeks, Sony initially blamed the software contractor First 4 Internet for the insidious piece of software, but pressure from the tech world kept mounting.

On November 18, a release from Sony claimed that it would "shortly provide a simplified and secure procedure to uninstall the… software if it resides on your computer." It has also announced a mail-in rebate program for consumers with infected CDs.

Since then, Sony has been lambasted in the media for its tepid response to a gross violation of its customers' trust. The rootkit software was installed without customers' knowledge, and several viruses have since been discovered that exploit the rootkit as an anchor in the depths of the computer.

A patch has since been issued but remains buried on the Sony BMG site in the FAQ section.

Lawsuits were quick to follow. In November, the state of Texas sued Sony under new anti-spyware legislation, and later the Electronic Frontier Foundation, a champion of freedom of electronic information, sued as well.

A provisional settlement, still requiring court approval, was reached in Texas just a few days ago. It requires Sony to offer monetary compensation to every person who bought an infected CD.

Unfortunately, the company can do so in the form of up to three free album downloads from iTunes or any other music downloading service. It is also forbidden to use the rootkits in question, although the order stops short of banning spyware use altogether.

The lawsuits focus on the issue of whether the End-User License Agreement (the little box that asks you to agree to the terms of installation of the CD's software) gives users adequate warning of the rootkit's presence.

Most analysts agree that the rootkit isn't even mentioned and, further, that it installs itself as soon as you put the CD in your player, well before you click the "OK" button to agree to the EULA.

But the lawsuits also raise larger issues of how far entertainment companies can go to ensure their intellectual property remains uncopied.

On many fronts, from suing music fans for MP3 collections to confiscating camera phones at film screenings, they appear to be alienating the very people who keep their companies afloat.

In the days after the rootkits were exposed, Thomas Hesse, president of Sony's global digital business, was quoted on NPR as saying, "Users don't know what a rootkit is, so why should they care about it?"

Hence this article, whose purpose is to tell music fans exactly what a rootkit is, why they should care and why it might be a good idea to refuse to buy products from Sony ever again.