Apart from using anti-virus software,
there are plenty of simple measures you can take to help protect yourself and your company against viruses and worms. Here are a few top tips for trouble-free computing.

Don't launch unsolicited programs or documents.
If you don't know that something is virus-free, assume it isn't. Tell people in your organisation that they should not download unauthorised programs and documents, including screensavers or joke programs, from the internet. Have a policy that all programs must be authorised by an IT manager and virus checked before they are used.

Don't use documents in .doc and .xls format.
Save Word documents as RTF files and Excel spreadsheets as CSV files. These formats don't support macros, so they can't spread document viruses. Tell other people to send you RTF and CSV files. Beware though! Some document viruses disguise the format. To be absolutely safe, use text-only files.

Use software patches to close security loopholes.
Watch out for security news and download patches. Such patches often close loopholes that can make you vulnerable to viruses and internet worms. IT managers should subscribe to software vendors mailing lists such as that at www.microsoft.com/technet/security/bulletin/notify.asp. Home users who have Windows computers can visit windowsupdate.microsoft.com, where you can scan your PC for security loopholes and find out which patches to install.

Block files with double extensions at the gateway .
Some viruses disguise the fact that they are programs by using a double extension, such as .TXT.VBS, after their filename. At first glance a file like LOVE-LETTER-FOR-YOU.TXT.VBS looks like a harmless text file or a graphic. Block any file with double extensions at the email gateway.

Block unwanted file types at the email gateway .
Many viruses now use VBS (Visual Basic Script) and Windows scrap object (SHS) file types to spread. It is unlikely that your organisation needs to receive these file types from outside, so block them at the email gateway.

Subscribe to an email alert service.
An alert service can warn you about new viruses and offer virus identities that will enable your anti-virus software to detect them. Sophos offer a free alert service. For details, see www.sophos.com/virusinfo/notifications.

Have a separate network for internet machines.
Maintain separate networks for those computers that are connected to the internet and those that are not. Doing so reduces the risk that users will download infected files and spread viruses on your main network.

Use firewalls and/or routers.
A firewall admits only authorised traffic to your organisation. A router controls the flow of packets of informatuion from the internet.

Configure your internet browser for security.
Disable Java or ActiveX applets, cookies, etc., or ask to be warned that such code is running. For example, in Microsoft Internet Explorer, Select:

and select the security settings you want.

Make regular back-ups of all programs and data.
If you are infected with a virus, you will be able to restore any lost programs and data.

Change your computers bootup sequence.
Most computers try to boot from floppy disk (the A: drive) first. IT staff should change the settings so that the computer boots from the hard drive first. Then, even if an infected floppy disk is left in the computer, it cannot be infected by a boot sector virus.

Write-protect floppies before giving to other users.
A write-protected floppy cannot be infected.

Safety guide taken from Sophos