Photos: How does spyware get on your PC?

Speaking at the Virus Bulletin 2005 conference in Dublin, Eric Chien, senior antivirus researcher at Symantec, outlines the common ways users are picking up spyware. Pop-up windows which suggest security updates and clock settings are available, or new messages are unread, often tempt less security-minded users to click.

"We've actually seen people create a full screen pop-up of a fake 'blue screen'," said Chien. Users are forced to act out of the belief their machine has crashed.

Chien said there are currently around 11,000 families of spyware applications and those intent on getting the malicious software onto users' machines are coming up with almost as many ways of doing so.

All photos: Will Sturgeon