Most viruses come through attachments and downloads from the Internet. Many people don't use the common standard of file recognition. The file recognition rule states that if you are not aware of what the extension or document is; do not download it at all.

An attachment can be a document, .EXE file, JPEG file or even a music file. These files can be small in nature but also very powerful because once you open these files, they can have an adverse impact on your system that you may never recover from.

A great example is 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 these address books and attach itself to emails that were sent out from the system. That means that if you sent an email to a person in the address book and they received it then their address book became infected also. The rule is to never trust a suspicious email which in the subject line looks odd. You should delete that email immediately. You should have a virus scanner to run through all emails as they go out and come into your system.

Downloads are another issue that can give a system problems. If a site is telling you to download software to view a web page, don't do it at all. The file may contain a certain virus that can embed itself into the applications part of your system and make applications real hard to open and use. Some of these viruses ca record your computer IP or keystrokes and steal personal information that you don't want to be known to hackers.

Unless you really know the company that the software is coming from, do not download software from the web. The best bet is to leave it alone and go with a reputable company that you know have safeguards and security certificates regarding the download of software.

When dealing with attachments and downloads, take extreme care so that you don't damage your system.