"Male. Obsessed with computers. Lacking a girlfriend. Aged 14 to 34. Capable of creating chaos worldwide."

The above description is the profile of the average computer-virus writer, according to Jan Hruska, the chief executive of British-based Sophos PLC, the world's fourth-largest anti-virus solutions provider.

"They have a chronic lack of girlfriends, are usually socially inadequate and are drawn compulsively to write self- replicating codes. It's a form of digital graffiti to them," Hruska added.

To create and spread cyber infections, virus writers explore known bugs in existing software, or look for vulnerabilities in new versions.

With more and more new OS (operating system) versions, there will be more new forms of viruses, as every single software or OS will carry new features, and new executables that can be carriers of the infection.

Executables are files that launch applications in a computer's operating system, and feature more prominently in new platforms like Microsoft's Windows 2000 and Windows XP than they did in the older DOS or Windows 3.1.

Virus writers also share information to create variants of the same infection, such as the Klez worm, which has been among the world's most prolific viruses.

The Klez, a mass-mailing worm that originated in November 2001, propagates via e-mail using a wide variety of messages and destroys files on local and network drives.

But the news gets worse. Recent events have uncovered what may be a new trend: spammers paying virus writers to create worms that plant an open proxy, which the spammer then can use to forward spam automatically. Many suspect this occurred with the SoBig virus.

The Sobig worms, began spreading in the early part of 2003. The unusual thing about them was they contained an expiration date and were given a short life cycle to see how features worked in the wild.

Having an expiration date also makes the virus more dangerous, because most people would have been alerted to the new worm within a few weeks and anti-virus definitions would have been updated.

A variant of Sobig, Sobig-F was so efficient that just a few infected machines could send thousands of messages. Sobig-F created a denial-of-service effect on some networks, as e- mail servers became clogged with copies of the worm.

According to Mikko Hypponen, manager of anti-virus research for Finland-based F-Secure Corp, Sobig-F sent an estimated 300 million copies of itself.

Computer Economics, Inc. states, "Nearly 63,000 viruses have rolled through the Internet, causing an estimated $65 billion in damage." However criminal prosecutions have been few, penalties light and just a handful of people have gone to prison for spreading the destructive bugs.

Why is so little being done? Antiquated laws and, for many years, as crazy as it sounds, a "wink, wink" or even admiring attitude toward virus creators.

One person has been sent to prison in the United States and just two in Britain, authorities say. But the low numbers are "not reflective of how seriously we take these cases, but more reflective of the fact that these are very hard cases to prosecute," said Chris Painter, the deputy chief of computer crimes at the U.S. Department of Justice.

So what can you do to protect yourself against computer viruses?

Well, first and foremost, make sure you have proven anti-virus protection like like Symantec's Norton Anti-Virus or McAfee's ViruScan.

In addition, If you haven't already done so, I highly recommend installing Microsoft's Service Pack 2. SP2 tightens your PC's security with a new Windows Firewall, an improved Automatic Updates feature, and a pop-up ad blocker for Internet Explorer. Plus, the newly minted Security Center gives you one easy-to-use interface for keeping tabs on your PC's security apps.

"Male. Obsessed with computers. Lacking a girlfriend. Aged 14 to 34. Capable of creating chaos worldwide."

Now, I'm no psychiatrist, but to me, the above description sounds more like someone with a few "bats in the belfry!"