But if you don't mind a bit of a diversion before I get going, I want to tell you about this friend of mine. He's ok - regular kind of guy - likes a drink with the best of them, sociable sort of bloke. But he has a Failing -

He's totally promiscuous.

He can't think about anything else. He's at it every night. I don't know how he finds time to sleep. He will consort with others at the drop of a hat, with no hesitation, no restraint, no shame. Or at least, his computer will. We are talking computers, here, right? As far as computers go, his innocent-looking Digital Venturis 5100 120 Pentium, that looks as though butter wouldn't melt in its floppy-drive slot, makes Madonna look like a nun. Other computers coasting by on the digital highway cast an eye over its beige form and make rude remarks about its I/O ports.

If there's a free download going, he'll download it; if there's a free bit of animation going, he'll animate it; if there's a button he'll click it. He even spells my name 'Jonez'. And it's not his space bar that is the most worn key on his keyboard: it is the shift key.

His Windows desktop looks like a spaceship console, and I don't dare to look at his hard drive. I am sure that the only legal software he possesses is Windows itself.

But - and this is where this is all leading to - despite the fact that he hangs around the most disreputable sites on the web; despite the fact that he spends all his time downloading dodgy files; despite the fact that his system is probably the most vulnerable in the universe - he has never had a virus!

Now, this is where this gets difficult. But I can hold my head up high. I am not like my friend. I don't go to disreputable sites. I have nothing to be ashamed of. It's just ... it's just that ... once in my past ... I ..

All right, I admit it - I once caught a virus. It was called Ripper, and when I got a new virus checker I immediately realised the horrid truth. I subsequently discovered that about half my floppy disks were infected.

Oh, the shame of it! Even now I blush at the memory. There I was, a clean-living chap, trying to maintain a moral lifestyle, presenting a clean-cut image to the world, and all the time my chips were suppurating with electronic corruption! Not very nice, I can tell you.

It was interesting that when I tracked it down, I discovered that it had arrived on a piece of commercial software.

But the point I really wanted to make was that in fact the risk of picking up a virus is still, if my experience is anything to go by, very small.

So why I am constantly receiving virus warnings, like the above?

The answer is, of course, that most of them seem to be, like the one above, completely bogus. It just amazes me though that people who are otherwise highly intelligent and logical seem to be unable to see through them. For example, in the one above, we suddenly get to a highly technical part: This virus will attach itself to your computer components and render them completely useless. Right. Can you run that by me again? I see, so theoretically if I take the case off, and go over the computer with a vacuum cleaner, I should be able to remove those clinging viruses and my computer components should once again become useful. Glad it's not difficult to deal with.

But why are we so willing to believe messages like this one? And does it matter?

For some reason the Internet is a breeding-ground for paranoia. People who are not on it tend to be paranoid about it - they see it as a hive of terrorists and paedophiles. People who are on it tend to think that it is full of people who want nothing better than to attack their system.

As for whether it matters or not ... The other week I received one of these things from a net friend. It was about Real World viruses rather than the computer types, and told a horrifying story about how someone infected with the HIV virus was going round leaving infected needles on cinema seats and in return coin slots on phones. As far as I recall, the cinema seat one had an added touch that there was a note, informing the victim they had been infected.

Now, that one, I think, does matter. The victim becomes the person attacked. All of us who are sexually active are vulnerable to the possibility of HIV infection, however remote that possibility might be. If we were to be infected, we would quite rightly see ourselves as victims. But in this little story, the people who are victims suddenly become transformed into the aggressors - instead of the victims of the virus they become transformed into its personification. That seems to me to be a very sinister view, and something that comes from the very underbelly of the human psyche.

There is an excellent article on this particular urban legend and others at http://korova.com/virus/hoax981128.htm

Possibly we are straying a bit too far here, into the realm of urban legends. But on the other hand perhaps there is a very close connection between these and the virus warnings we receive.

Logically, a very fundamental question which should be addressed is ‘What is a virus?’ Most people will give a definition that begins ‘A self-replicating piece of code that ... But of course, you could consider a virus in terms of the damage or inconvenience it causes.

I once tried out a piece of commercial software from a free computer magazine disk. After about two seconds I decided I didn’t want it, and uninstalled it from my system. However, I discovered that it had left a calling card, in the form of a logo, which appeared on my screen even before Windows did. (I was using 3.1 at that time). I won’t tell you the name of the company, but I will say that I became thoroughly sick of this letter ‘A’ which ultimately required acrobatic manoeuvres to get rid of. It could not be found in the initialisation file, or the system initialisation, the desktop, or indeed anywhere at all.

In the end I decided that the only way of doing it was to delete, one by one, every file in the Windows directory and then reboot Windows each time. That is an activity that ranks with building a scale model of the Taj Mahal out of used toothpicks. After several rather tedious hours I discovered the culprit. It was a file called something like ‘Sdzr.dat’, obviously to make it easy to find.

Now as far as I am concerned, that was a virus. Its replication method was different from the normal way, but in all other respects it had the characteristic effects of a virus, in that it affected the display of the computer, and was deliberately hidden. Interesting that it was another one that came from a commercial company.

So it occurred to me that these virus hoaxes, like the one at the beginning of this article, are very similar, and that they themselves could actually be considered a form of virus. They are not self-replicating - people do that for them - but their replication method is very successful indeed. They take up space on hard drives, and they tend to clog up the system, affecting downloading times.

So, how can one tell the hoaxes from the real warnings?

Well, there are some basic things you can do to protect your system. For example, always scan attachments to e-mails and executable files with a virus checker. If you make sure you do these two things you will be pretty safe. So do we really need these warnings anyway? If you take the standard precautions it does you no good at all to know about the latest deadly peril to threaten your system. In recent years the only thing that perhaps we could have profitably been warned about is the charmingly named Back Orifice, about which, of course, I never received a warning.

The next time you receive one of these warnings, before forwarding it to somebody else, why not visit www.ciac.org? This is a site where you can find the latest details about new viruses and new hoaxes, and you will be able to decide which category your e-mail message falls into.

In other words, before alarming your friends, why not check to see whether there is really something to be alarmed about? And whether you are doing the opposite of what you think you are doing. Whether the warning is the virus itself, the medium literally being the message.

Right. That's that. Now, about those messages that are entitled "If Bill Gates were a car mechanic" or "101 Things You Can Do With a Cigar" ...