A "Zombie Computer" refers to a computer that has been compromised by malware, allowing it to be controlled remotely by a hacker without the owner's knowledge. These infected machines are often part of a larger network known as a botnet, which can be used to carry out various malicious activities, such as sending spam emails or launching DDoS attacks against websites. Zombie computers are typically infected through malicious software that users unknowingly download, often bundled with legitimate software or through phishing attacks. Once compromised, the computer continues to function normally for the user, making it difficult to detect the infection. Protecting against zombie computers involves using up-to-date antivirus software and practicing safe browsing habits.