By Ollie Randall
Malware is short for malicious software which covers things like computer viruses and worms which can damage your PC.
A computer virus is used to infect other PCs and can delete files and can use up memory. They are usually carried through attachments.
A worm does similar things to a virus but can travel unaided, making them more dangerous.
A trojan horse can infect a PC when a user loads a non-legitimate site. They can delete files, cause annoying pop-ups and change desktops.
Spyware is used to gain access to personal details like login details or your PC's IP address.
Adware causes unwanted adverts to appear on your PC.