7. Other pests

Worms

These are a bit like a computer virus but they spread on their own through computer networks. Their biggest problem is the sheer amount of computer time and bandwidth they soak up, so making the network slow to a crawl.

Adware / Spyware

These are programs designed to keep track of which adverts you click on and then they send specific adverts to your browser. Fairly harmless but annoying and hard to get rid of.