What is a virus, trojan or worm?
A virus is just a computer program. Like any other program, it contains instructions that tell your computer what to do. But unlike an application, a virus usually tells your computer to do something you don’t want it to, and it can usually spread itself to other files on your computer – and other people’s computers. If you’re lucky, a virus will execute only a benign “personality quirk,” such as causing your computer to make seemingly random bleeps. But a virus can be very destructive; it could format your hard drive, overwrite your hard drive boot sector, or delete files and render your machine inoperable. Computer viruses are the “common cold” of modern technology. They can spread swiftly across open networks such as the Internet, causing billions of pounds worth of damage in a short amount of time. Five years ago, the chance you’d receive a virus over a 12-month period was about 1 in 1000; today, your chances have increased to about 1 in 10. Viruses have been developed into various
