1. Computer Virus - this is a phrase coined from biology to describe a piece of software that behaves very much like a real virus.

2. A computer virus is a software programme that is designed to copy itself multiple times, to attach itself to other programmes. Viruses do not damager the hardware of a computer, they affect the data and files stored on your computer. Early viruses were relatively harmless, they were just annoying. But since the first viruses in the 80s, viruses have been created to corrupt and delete files, as well as trying to copy itself everywhere.

3. The most common way to get a virus is to open an e-mail attachment or visit a website that contains a virus. Other ways to get a viruses is to load an infected file onto your computer from a floppy disk, memory stick, CD-Rom or DVD. Virus’s don’t always have immediate effects. It could be on your computer for a while but you wouldn’t notice it until it starts to mess up your computer. A virus is spread by allowing it to run on your computer. So any file or programme can contain a virus.

4. As computer viruses have become more of a problem, companies have begun making anti-virus software. Anti-virus software removes and protects your computer from viruses. Anti-virus programmes, detect a virus pattern and alert the user of them. Anti-virus software can be a problem when new files a installed. They think these new programmes are viruses. There is usually a annual fee to pay for these ant-virus programmes, but its worth it to make sure your computer is safe from viruses.

5. Viruses can be prevented by: Using anti-virus programmes Scanning in coming e-mails Not opening attachments from people you don’t know. Not allowing people to upload their files onto your computer using storage devices. Not using software that's been copied. Backing up your system regularly.

6. Other pests include: Trojan software This is an application that appears to do something useful such as a computer game (which is why you loaded it on to your computer in the first place) but quietly, behind the scenes it is doing something with ill- intent Worms These are a bit like a computer virus but they spread on their own through computer networks. Their biggest problem is the sheer amount of computer time and bandwidth they soak up, so making the network slow to a crawl Adware / Spyware These are programs designed to keep track of which adverts you click on and then they send specific adverts to your browser. Fairly harmless but annoying and hard to get rid of.