The Motherboard (also called a system board, or circuit board) is the most important part of the system. Acting as the foundation of a computer, the motherboard supplies all of the electrical connections for the various components, including the CPU and SIMM cards (see RAM), inside the computer.

The Central Processing Unit (CPU) is the brain of a computer. It is responsible for processing instructions and carrying out users' commands. Other parts of the computer serve the CPU, which is also known as the microprocessor, enabling it to do its job.

RAM (Random Access Memory) determines how many projects can fit on the desktop at one time. When a program is run, it is loaded from the hard drive into RAM. Ultimately the more RAM there is, the more programs and files can be opened at once. It must be remembered to save on a hard drive or diskette any work that it is intended to be kept, because whatever is in RAM is erased when the computer is turned off. RAM chips, the physical components that contain the memory are grouped in rows called SIMMs (or single in-line memory modules). These modules are small bars, usually containing eight, or nine memory chips . To add more memory to the computer, just plug in one or more SIMMs. A Memory Chip is the integrated circuit that actually contains the RAM

ROM (Read-only Memory) contains the commands the computer needs to activate itself. Instructions in ROM let the computer start when the power is turned on, and, unlike RAM, its contents are retained even when the power is off.

The Diskette Drive reads and writes information on diskettes which are small-capacity storage devices that usually hold 360,000 or 1,440,000 characters . Since a diskette can be removed from the drive and be replaced by another, a diskette drive allows access to a virtual unlimited collection of data.

A Hard Drive or hard disk, or fixed disk acts as a computer's filing cabinet. A hard drive allows the most rapid access to data and can store billions of characters.. Hard drives provide the primary storage space for the computer's operating system and all program and data files. Like the motherboard and random-access memory (RAM), a failed hard drive can render a computer useless.

A CD-ROM drive reads information from CD-ROMs, the high capacity medium used for most multimedia storage. Like diskettes, CD-ROMs are removable. Recently technology allows CD-ROMs to be written to, and erased.

A Sound Card is an expansion card that lets a computer produce sound. Examples of practical uses for sound capabilities include games, music applications, and interactive educational software.

The Expansion Card is a circuit board that slides into an expansion slot. It is used to add peripherals, such as a sound card or modem, to the PC.

An Expansion Slot is an opening on the motherboard into which a board or card can be inserting, expanding the capability of the computer.

The Power Supply is the vehicle through which electricity is regulated and sent to the various components of a computer.