Attack of the zombies

Viruses can be used to turn your PC into a zombie. The virus loads itself quietly into the computer then when its activated your computer and thousands of other infected computers worldwide start to send data to a target computer. This in effect swamps the poor target computer causing it to be unable to work properly. Often these so called 'denial of service attacks' using an unwitting word-wide army of zombie PC's are used to blackmail companies who need to have their websites working to do business such as online banks and betting services.