A Personal Computer (PC) Is Analogy To A Car
Main PC components:
The Motherboard (PCB) including the CPU is equivalent to the Engine.
The Hard Drive is what the car can carry (car body and trunk).
Other PC components:
CD/DVD Drive, RAM, Video Card, Network Cards, USB connectors, and other accessories are equivalent to components that will help the car go farther, more efficient and comfortable such as gas tank size, Electronic Fuel Injection (EFI), suspension system, power steering, anti-locked brakes (ABS), etc…
Driving your car from a ramp onto a highway is equivalent to connect your computer to the Internet.
Just as the highways connect you from one city to others, the Internet will connect you to many destinations all over the world. Another word, the Internet is a much larger network that can take you to many places than highways.
PCB = Printed Circuit Board
CPU = Central Processing Unit
RAM = Random Access Memory