16 Malware are malicious software designed to damage your computer . Example:-Viruses, Trojans, Worms, Spyware.
17 A virus can enter PC via infected discs or internet. A worm spreads through e- mail attachments.A Trojan horse is disguised as useful program but may attack data security.Spyware and adware collect information from your PC. They come with ads and free downloads.