The most dangerous and difficult computer virii are known as Rootkits -- because they install at the lowest levels (the roots, if you'll excuse the bad metaphor) of your computer's Operating System.  This makes it possible for the virus to hide from discovery by virus scanners, process listers, or folder directories.

It is never an acceptable practice to install software on someone's computer without permission.  This is the behavior of virii and spyware.  If caught, people go to jail for this, and/or pay heavy fines.  Who would do this?  Dr. DataDeath?  Kevin Mitnick?  How about SONY!?!

In an analysis at http://www.sysinternals.com/blog/2005/10/sony-rootkits-and-digital-rights.html, Mark Russinovich details his discovery that his new CD, ironically entitled Get Right with the Man by the Van Zant brothers, installed a Rootkit on his computer.

It appears that Sony's aggressive copy-protection software is the Rootkit.

It's funny -- by installing this malware, Sony has just given us a reason to use Peer-to-Peer software to download its recordings: it's safer than buying the CD!