As if you didn't already have enough worries. The wary computer user already feels bunkered in and hunkered down, in between hiding behind firewalls, running anti-virus programs and keeping a watchful eye on suspicious-looking e-mails.

You have to look out for infected files on floppy disks, panic over the latest holes in e-mail programs, and be cautious with how you set up company and personal websites. It's almost enough to send you back to a manual typewriter.

Now comes an insidious screensaver virus - a new computer devastator that sneaks into your system via an e-mail and sets up a screensaver which lets some badguy hacker control your computer remotely, download files, and all that other stuff that appears in Tom Cruise films but which we would all rather believe couldn't happen in real life.

According to security software company Network Associates, Backdoor-G is a so-called "trojan horse" program, which arrives into your computer hidden inside an attack program which potential victims receive as an unsolicited e-mail. The program has reportedly taken the form of both a screensaver and an update to a computer game.

Open the e-mail and the program installs itself, allowing Backdoor-G to turn the victim's computer into a client system. In other words, it allows a hacker to operate the victim's computer remotely over the Internet. The hacker can thus gain access to just about anything on the victim's computer.

Unfortunately, it's also almost impossible to detect once it executes because it is capable of changing its file name. And according to Network Associates, it spreads everywhere in your computer's system.

Admittedly, the screensaver aspect of this virus has its amusement potential - hmmm, can't we all imagine a bitter and twisted screensaver we'd like to design to announce our conquest of the computer belonging to some particularly detested person in our lives? But the arrival of Backdoor-G is probably more apt to make you sigh in exasperation.

Computers were supposed to make life easier, more manageable, more controllable. Okay, you can stop laughing, but you know what I mean. Instead, they just seem to bring more stress, hair loss, heartburn and overly-chewed fingernails.

But it's perhaps wise to remind computer users that many, if not most, aggravations come not from the machines or even, sometimes, the software. They come from humans who still make far too many assumptions about what computers, software, and the Internet can or cannot do.

Partly, that's our fault, because we accept products from hardware and software vendors which in any other industry would be considered too unreliable, unstable and under-tested to be released onto the market.

We believe the vendors when they excuse themselves by telling us it's all too complicated to explain, it's the nature of the medium and so forth. That's appalling, but as long as we lack the collective spine to demand better, we're stuck with what we get.

But it's hard to see how we can obliterate the virus problem, since a computer is a sitting duck for viruses because of the way in which we use them - sharing disks, transferring files, going on and off the Net and downloading things from places we don't know. Few people take even basic precautions against viruses and so, these things spread. In addition, many people never bother to make backups of their work, and thus are twice-devastated if struck by a virus or another form of computer attack.

And even if the anti-virus software makers come up with a fix to one virus, some hacker is always brewing another that we cannot yet imagine. In the days that it takes to create an antidote, thousands or millions can be hit.

In the case of particularly nasty viruses, entire companies can be brought down at the cost to the global economy of billions of pounds.

So what's a poor computer user to do? There's not much else to recommend but to proceed with caution, which means educating yourself on how to keep your own machine as clean as possible by being vigilant against viruses and other forms of computer attack.

Buy a good virus-scanning software package and use it. Be wary about what you download off the Net and scan it first. Don't open e-mail with attachments unless you know the sender (and even then, be cautious about all attachments).

And create backups. Anyone who has ever lost irreplaceable, important files off a floppy disk or hard-drive knows the excruciating pain of that particular experience.

You may still have to clean up a computer if a virus brings it down - and that's not a pleasant task - but having your files intact somewhere else at least keeps the misery from reaching bottomless depths. [SBX]

A detector for the Backdoor-G virus is online at www.nai.com

Karlin Lillington is at klillington@irish- times.ie