The vast majority of viruses enter systems via attachments and downloads from the Internet. Most computer users don’t use the common standard of file recognition – the file recognition rule states that if you are not certain as to the extension or document then don’t download it at all.
Attachments come in many shapes and sizes – a .EXE file, JPEG file or maybe even a music file. Often these files are small, but also very powerful because, once opened, they can create severe and adverse effects on your system, some of which you may never recover from.
A good example would be the “Typhoid Mary” virus which was an email attachment that attached itself to address books of users in Microsoft Outlook, Eudora or any other email client. The purpose of the virus was to infect those address books and then attach itself to all outgoing emails that were sent out from that account.
That means that if you emailed a person in your address book and they received it, then their address book would became infected too. The rule is to never trust a suspicious looking email which has a dubious subject line. You should delete such emails immediately. You should have a virus scanner to run through all emails, both inbound and outbound.
Downloads are another issue that can cause your system problems – if a site instructs you to download software to view a web page then don’t do it! The file may well contain a certain virus that can embed itself into the applications part of your system, making the applications you run slow down or fail to open at all. Some of these viruses can record your computer’s IP (internet protocol) address, or keystrokes, and steal your personal information.
Unless you are certain that you can trust a particular website, then don’t download any software they recommend. The best bet is to leave it alone and go with a reputable company that you know have safeguards and security certificates regarding the downloading of software. When dealing with attachments and downloads, take extreme care so that you don’t damage your system.
And, of course, the most important means of staying virus free is to install good antivirus software.