Anyone's email inbox has (at some point) been clogged with so-called spam messages. Spam, or unwanted advertising, is the plague of the Internet and can cause many problems, from viruses to blocked email inboxes due to an overload of spam messages. Over the past few years there has been a significant rise in spam. Consumers often wonder where all these unwanted messages are actually coming from. It is very likely that other consumers just like you are sending them. They might even be sent from your own computer. Clever hackers can use your PC to send out spam messages all around the world.

When a hacker attacks (or 'hijacks' a PC) the computer is used as a "zombie computer." This means that your PC can be used to perform tasks controlled by the hacker. By downloading a malicious very small program (or code) onto the computer, the PC can be used to send out spam messages. Often the owner of the PC does not even know what is going on. Microsoft engineers have performed tests to see how easy it would be to hijack a PC and came to the concluding that it was a very easy thing to do.