There are a tiny number of mobile-phone viruses compared to the threat on the Windows platform.

Trojans are different from viruses because they can lurk in PCs without anyone noticing and can spy on the computer user's activities then send this information back anywhere in the world.

If he had been scanning his email for viruses he would never have received the message from the Sober worm. If jailed he'll have plenty of time to reflect on whether he should have believed everything that was sent to him via e-mail.

To the untrained eye Mytob and Zotob can appear quite different: one group of viruses travels via email, the other primarily by exploiting a Microsoft security hole.

And Windows XP SP2 is having an effect, what with its primitive firewall and its status center that tells users if their anti-virus signatures are out of date,

And Windows XP SP2 is having an effect, what with its primitive firewall and its status center that tells users if their anti-virus signatures are out of date.