What is a virus?
A virus is a computer program that runs on your computer without your knowledge. Viruses are designed to replicate themselves when they are run, so that every part of your computer becomes infected. Once this happens, you can easily spread the virus to others through files and emails.
How does that affect my security?
Viruses can be used to track what you do on your computer - and they can give unauthorized access to your security details. They can also make your computer behave strangely, from annoying but harmless problems like playing music or displaying messages to something far more serious such as changing or deleting files, or even wiping the contents of your hard drive.
What can I do?
Make sure you have the latest antivirus software installed on your computer. You should make sure that your operating system is up to date with all of its patches. Be careful about the sites you visit and files you download. Treat all spam email with suspicion.