A computer virus is a self-replicating computer program written to alter the way a computer operates - without the permission or knowledge of the user. The virus typically infects by being accidentally downloaded or sent via an email attachment.

The virus, when it infects, will then replicate itself as well as generally damaging your computer in some way.

• Email virus - This virus type uses email as mode of transport to infect your computer and is generally via an attachment you receive. These viruses often copy themselves by automatically mailing copies to hundreds of people in your address book. The virus will infect once the email attachment is opened.
   
• Trojan - This is a computer program that is disguised as or embedded within legitimate software. It may look useful or interesting (or at the very least harmless) to you, but are actually dangerous when run. Trojans also allow computer hackers can gain access to your passwords and personal information as well as download illegitimate software on to your computer.

  For a Trojan to infect, it must be invited onto a computer by the user opening an email attachment or downloading and running a file from the internet.

• Worm - A worm is a piece of software that uses computer networks and security flaws to create copies of itself. It does this by scanning the network for any other machine that has a specific security flaw. Once found, it replicates itself to the new machine using the security flaw, begins scanning, replicates and causes damage.

  Worms generally exist inside of other files, often Word or Excel documents.

The best advice to not download files from unknown sites and don’t open emails from unknown addresses. Further protect your computer by enabling Email Anti-virus on your Slingshot mail box and installing NOD32 Anti-virus software.