Bug busters: keeping your PC virus free

With more computer viruses reported every day, it may seem like we're fighting a losing battle but there are plenty of simple ways to keep your PC safe from harm. Let us show you how.

If you think worms are the gardener's friend and 'SoBig' is something you say when you're gesticulating to the assistant in B&Q's timber department, then count yourself lucky.

For the rest of us, these words are increasingly familiar and the bad news is that they're part of a growing vocabulary used to describe threats lurking on the internet.

Computer viruses, worms and Trojans are far from recent inventions, but it's only recently that they've become a serious problem.

In the early days of personal computers, pretty much the only way to contract a virus was to use a floppy disk that was infected with one. And, unless you went to floppy swapping parties, the chances of your computer contracting something unsavoury were slim.

Today, however, just about every computer is connected to just about every other computer through the internet and the internet is the electronic equivalent of a high-street hot dog seller when it comes to picking up bugs.

All it takes is one virulent virus and computers all around the world are at risk from infection. Unfortunately, virulent viruses are on the rise.

However, it's not all doom and gloom. Protecting your PC from viruses isn't difficult and needn't be expensive but it does require some diligence on your part.

A little effort goes a long way and, with some sage advice from Computeractive, you can sit safe in the knowledge that virus infections are things that only ever happen to other people.

101 damnations
Despite their biological names, viruses and worms are nothing more than programs, just like all of the other programs you use on your PC.

The difference, of course, is that viruses and worms have been created with malicious intent and all have been designed to spread as far and wide as possible.

True computer virus infections are rare these days, since true computer viruses can only be spread using an infected application or disk.

It's almost unknown for a manufacturer to release a virus-infected application or CD-Rom, and floppy disks - the main method for virus transmission - are used far less widely than they used to be.

It's still possible to download infected applications from the internet but again, any website worth its salt will check its software for viruses before putting it online.

Worms, on the other hand, are on the rise. The terms 'virus' and 'worm' are used interchangeably but technically speaking, a worm is a program - usually, but not always malicious - that spreads over a network and the internet is nothing more than network, albeit on a global scale.

Most worms need a helping hand to get around and they usually start with an email in your inbox. The email often contains a short message along the lines of 'here's that file you asked for' and is often from a recognised sender.

The attachment it carries appears innocuous enough, so the automatic response of most people is to open it, which is a big mistake.

First, no human being sent the email - a worm-infected computer did. Second, the attachment isn't innocuous - it's the worm itself. Some worms take the form of a macro stored in a seemingly ordinary Word.doc file but most are files with a double file extension that's designed to mislead.

An attachment called 'image.jpg.vbs', for example, isn't a JPEG file but a Visual Basic program. Whatever the scenario, open the attachment and you are infected by the worm.

What happens next with a worm infection depends on its payload. Most worms will surreptitiously pluck email addresses from your Outlook or Outlook Express address book and send infected messages to them.

Some will also perform irritating or harmful actions, such as resetting your computer when you connect to the internet or taking control of your computer to send out spam.

A few, however, go even further and attempt to launch denial-of-service attacks on websites on a particular date.

Wriggle free of worms
Worms are able to spread so quickly and easily because they cunningly exploit the weakest part of any computer system: the user.

Without complacent and foolish users who ignore virus warnings, fail to install antivirus software and click on anything that arrives in their inbox without thinking, worms would quickly dwindle into non-existence.

As it stands, worms are all over the place and most people who get them only have themselves to blame. So what can you do to keep your PC free from the plethora of pernicious programs circulating on the internet?

Unsurprisingly, common sense is one of the most effective counter measures and you should treat all unsolicited email attachments with suspicion. In other words, don't automatically open them.

If you use Outlook Express for your email, you should also make use of its secure settings. See below for more information on how to do this.

Unfortunately, some worms spread simply by looking for security weaknesses in computer systems, much like a car thief walks down a road checking for unlocked doors.

Security weaknesses and Windows seem to go hand in hand but to Microsoft's credit, it does issue patches to fix most weaknesses soon after they're identified.

The problem is that most people don't install them. The recent Blaster worm exploited a Windows security hole for which Microsoft had issued a patch a month before.

The lesson here is to keep your copy of Windows up to date. Windows XP users should use the automatic updates feature; users of other versions should visit the Windows Update site regularly. See below for more information on this.

Hands up those who don't have any antivirus software installed. Now take those raised hands and use them to slap your other wrist.

Everyone - we repeat, everyone - who owns a computer should install some antivirus software and, more importantly, keep it up to date. If you don't want to buy some, download AVG Anti-Virus - it's completely free and very good.

We also recommend that all broadband users install some firewall software. Windows XP's own firewall is better than nothing but the free version of ZoneLabs' ZoneAlarm is much better. Now get to work!

Please delete me
Believe it or not, there is actually something worse than a virus and that's a virus hoax. If you get an email claiming to be from Bill Gates, Microsoft, an antivirus company, a friend, a complete stranger or even Computeractive, warning you about a virus, asking you to delete a certain file and forward the message on to all your friends, don't. Simply delete the email instead.

Messages such as this have been circulating for as long as there has been email and they're little more than chain letters.

The files many of the emails ask you to delete are either harmless or crucial to the operation of Windows, so deleting them usually does more harm than good.

Unfortunately, it's easy for the unwary to fall prey to such 'warnings', more by ignorance than by anything else, so here's some simple advice: never, ever trust a virus alert that is sent by email, no matter how reputable the source seems to be.

Instead, put your trust in some good antivirus software and spend the time you saved not forwarding emails reading about virus hoaxes at the excellent Vmyths website.

Update your antivirus software
If you don't have any antivirus software installed on your computer, you're skating on thin ice and any advice you follow from the rest of this feature will be wasted.

AVG Anti-Virus is an excellent application which can be downloaded for nothing here

An antivirus application is only as good as its list of 'signatures': the information, a bit like fingerprints, that it uses to identify viruses.

As new viruses appear, so do new signatures and, unless antivirus software is kept up-to-date with new signatures, it won't be able to spot new viruses.

Norton Anti-Virus, like most others available, uses signatures. To start the program, click the LiveUpdate button and follow the on-screen instructions. Broadband users can also click the Configure button on the LiveUpdate dialogue box and set LiveUpdate to run automatically at set intervals.

AVG Anti-Virus can also be updated in a similar way. When you first install the program, you'll be offered an automatic update option and this is recommended for broadband users.

Otherwise, you can update the virus signatures by starting AVG for Windows from the Start menu and choosing Update from the programs Service menu.

Click the From Internet button and you can either specify an automatic update schedule or download any available updates manually.

Office updates
Unfortunately, Microsoft Office is just as vulnerable to worms as Windows but since Office isn't as ubiquitous as Windows, its updates aren't so widely publicised or as easily accessible.

Open Internet Explorer (other browsers won't work) and go to office.microsoft.com/officeupdate. From here you can browse for updates for all versions of Office, or let the website scan your PC to see what updates you need.

Office XP users will need the original installation CD to install the updates, but you can go to the Full File Update page and download updates that can be installed without the CD, although the process isn't quite as simple. You can find Office XP full file updates here.

USEFUL WEBSITES

AVG Anti-Virus
Excellent - and free - antivirus software.
www.grisoft.co.uk

Microsoft Security for Home Users
Useful page containing information about security updates in non-technical terms.
www.microsoft.com/security/home

Microsoft Office Update
Feature and security updates for Microsoft Office. Office is just as vulnerable to worms as Windows so make sure you bookmark this page and visit it on a regular basis.
http://office.microsoft.com/officeupdate

Windows Update
The site every Windows user should visit regularly for security updates.
windowsupdate.microsoft.com

Symantec
Antivirus software firm with an excellent website for virus information.
www.symantec.com

VMyths.com
This site purports to tell 'the truth about computer security hysteria'. The site is sadly no longer updated though, due to lack of funding.
www.vmyths.com

ZoneLabs
One of the best firewall applications currently available - and it's free.
www.zonelabs.com

WORKSHOP - KEEP WINDOWS UP TO DATE

STEP 1: Windows XP users with broadband should enable the Automatic Updates feature. Right-click on the My Computer icon, choose Properties and then click the Automatic Updates tab. Tick the 'Keep my computer up to date' box and select the 'Automatically download the updates ...' option. Use the drop-down lists to choose a day and time to check for new updates, then click the OK button.

Windows XP will now check for 'critical' updates whenever you're online at the time you specify and, if there are any, it will automatically download and install them (you may see message on-screen about this).

STEP 2: Users of other versions of Windows (or Windows XP users who don't want automatic updates) should regularly visit the Windows Update site. Open Internet Explorer and go to www.windowsupdate.com. When the site appears, click the 'Scan for updates' link.

STEP 3: Once the scan has completed, the left of the browser window will contain a list of Windows updates that you can choose to download. Critical updates - updates that Microsoft deems essential - are automatically selected but you must click the links for other updates to choose them.

To download and install the updates, click the 'Review and install updates' link and follow the on-screen instructions. You should repeat steps 2 and 3 every month, or whenever you read about a new Windows security problem.

WORKSHOP - SECURE OUTLOOK EXPRESS

STEP 1: Start Outlook Express and go to Tools, Options and then click the Security tab. Select the 'Restricted sites zone' option and tick the box for 'Warn me when other applications try to send email as me'.

If you tick the 'Do not allow attachments ...' box, Outlook Express will prevent you from opening attachments that may contain viruses, but this option may prove too restrictive for some people.

STEP 2: Start Internet Explorer and go to Tools, Internet Options and then click the Security tab. Click the Restricted sites icon, then click the Custom Level button. On the Security Settings dialogue box, choose 'High', from the drop-down list and click the Reset button.

Confirm your changes, then click on OK to close the dialogue box and then click on OK to close the Internet Options box.

STEP 3: Back in Outlook Express go to Tools, Options and then click the Read tab. Tick the 'Read all messages in plain text' box and click on OK. All of your messages will now appear as ordinary text, not fancy formatted web pages.

This will prevent messages from automatically downloading information and images from websites, which means you won't see images in spam either.