A Virus is a type of malicious software that replicates itself by inserting its code into other programs, files, or the boot sector of a computer's hard drive. It spreads from one system to another through infected files, often causing damage by corrupting data or disrupting normal operations, distinguishing it from other types of malware like Trojan horses or time bombs.

A Worm is a type of malware that autonomously replicates and spreads across computer networks by exploiting vulnerabilities in network protocols or operating systems. Unlike other viruses that may require user interaction or specific conditions to spread, worms can propagate rapidly and independently, infecting multiple computers without user intervention.

A modem facilitates communication between computers by converting digital signals into analog signals suitable for transmission over telephone lines, and vice versa. It plays a crucial role in enabling devices to send and receive data over traditional telephone networks, serving as a bridge for digital communication over analog infrastructure.

The F1 key on a computer keyboard is commonly associated with accessing the "Help" menu within software applications or the operating system. It provides context-sensitive help, offering users guidance, instructions, and troubleshooting tips related to the task at hand, making it a quick resource for resolving issues or learning more about software functionalities.