DEFINITION
A virus is a program (lines of executable computer code). Viruses are made to spread from machine to machine, and many of them use the internet to do this. Many use the address book and signature files of programmes like MS Outlook Express to hide in and spread. Others attach to attachments. Viruses which act in this way are called worms. For a detailed explanation of the difference between a virus, a worm and a trojan horse, visit this site. Some viruses are not harmful to your machine, but many are malicious and potentially embarrassing.
Another excellent resource is at this  webpage (https://www.comparitech.com/antivirus/computer-virus-resources/) : it has a list of viruses, hoaxes, anti-virus vendors and links to the anti-virus databases.

SIRCAM
The SirCam virus has unleashed havoc and many red faces over the last 10 days. It mails a random file on your hard drive to people in your address book. In addition, some systems recognise the virus and 'bounce' the mail messages, with their attachments, back to the victim. At a South African ISP last week, this happened when a user had her PC infected and the worm sent out a large (3MB) file as an attachment to everyone in her address book. The mail server was jammed within a few hours. Open the attachment, and your PC wil become infected. Were you a victim? Visit Slashdot and take the poll ...it might give you a smile.
Visit this web site for information on how to recognise and get rid of the SirCam virus.
Another virulent and destructive viruses at the moment:
Code Red Worm

HOAXES
Virus hoaxes are those irritating messages which warn people about terrible viruses which don't exist. These get circulated by email users as friendly warnings, and eat up bandwidth. Some of these hoaxes can be harmful: a recent hoax stated that a virus file had been found in the Windows sytem folder, and it had to be deleted as it was a virus. It was extrememly believable, and many people unwittingly deleted the file. Unfortunately, it is a necessary and legal part of the Windows operating system.
Some viruses are setup to look like warnings about viruses - and so people open the messages and their systems become infected.

REGEDIT
Often, the cirus will record keys in the Windows registry. In order to edit the Registry, you will have to click on start, click on run, type regedit and press 
You will be able to browse the different folder as in Windows Explorer: locate and delete the virus 'keys' if they are there.
Only follow specific and clear instructions which you have located on a reputable anti-virus web site. If you are unsure, check more than one site.
WARNING: DO NOT EDIT THE REGISTRY IF YOU ARE NOT CONFIDENT ABOUT IT - YOU CAN MESS UP YOUR MACHINE BADLY

TIPS
- don't send any email until you have cleaned your machine
- obtain a copy of the virus pattern file update from your sytem adminastrator, or vendor, and install and run a scan of your machine
- if there is no update available yet, search the internet for information on how to clean the virus, or bookmark this site
- If your system is damaged and you have to reinstall the operating system, backup but don't put the files back on your machine without scanning
- scan and clean any diskettes you have used during the 'infected' time
- always download and install the latest upgrades to your anti-virus software (this will usually be every 3-4 weeks)
- encourage this practise amongst your colleagues
- configure your anti-virus to scan incoming email and downloaded files over the internet