A PC consists of a number of visible components: the monitor (the display screen), a keyboard, a mouse, speakers (can’t have sound without speakers), and the computer itself (which is usually a medium-sized upright box). The monitor, keyboard, mouse, and speakers all connect into the computer. The mouse and keyboard draw power from the computer, but the monitor, computer, and speakers must each be plugged into the wall.

Monitors are connected to computers using one of a few different standard connectors; the most common today is called DVI. Though computers and monitors are often sold bundled together, just about any monitor sold today should work with just about any computer sold today (even Apple monitors usually work with non-Apple computers and non-Apple monitors usually work with Apple computers). Speakers are usually connected via the same standard mic jack used for standard headphones. Surround sound speakers generally use two or three of these connectors. Keyboard and mice are connected via a standard connector called USB (Universal Serial Bus). USB is used for almost all other kinds of devices, including portable audio players (iPods), cell phones, game controllers, printers, cameras, and many different storage devices, such as flash drives and external hard drives. A typical PC today has several USB connectors, though laptops usually have only two or three. A USB hub allows you to plug multiple things into one port, (just like a power strip allows you to plug multiple things into one wall power socket). USB is also designed to allow “hot-plugging”, meaning you can plug devices in and out while the system is running. For some devices, this may not always be a good idea: a storage device, for example, should not be unplugged while data is being written to it. (An icon in the Windows system tray allows you to “eject” these storage devices so that they can be removed without causing data loss.) USB actually uses 6 different plug types. The most common is a flat rectangle one centimeter wide. All 6 different plugs go in only one way, but it’s usually hard to tell whether you have the plug upside down, so you’ll often have to try both ways before the plug goes in.

Inside the computer itself, we have several key components:

                motherboard: a large, flat board of circuitry into which all other components plug into. Effectively connects all the components together. The motherboard also includes most of the connectors visible on the back of the computer.


CPU (Central Processing Unit): the processor which executes the program instructions. Because modern CPU’s run very hot, they need cooling by a heatsink and fan when operating or else they’ll malfunction.

                RAM (Random Access Memory): chips used for data storage. RAM is much, much faster than a hard drive, so it is used for holding the code and data of running programs. However, RAM is volatile (meaning it loses its data when it loses power), so RAM cannot be used for storage of files (or else they would disappear when we turn the computer off).

Hard drive: though a PC can have any number of storage drives, we expect a modern PC to have at least one hard drive built inside on which to store at least the operating system and programs. Most hard drives today connect to the motherboard via a standard connector called SATA.

DVD drive: a PC can run fine without a DVD or CD drive, but most programs and Windows itself are usually installed from DVD discs, so even if you never watch DVD’s on your computer, it’s still good to have a DVD drive. DVD drives today connect to the motherboard via SATA or an older connector called IDE.

Expansion cards: an expansion card is a board of circuitry which plugs into the motherboard via an expansion slot. A few key pieces of functionality that used to be provided only by expansion cards are today typically built directly into the motherboard at lower cost, including sound, networking, and video. However, the video capability built into motherboards is generally far inferior to what can be found on a decent video expansion card (at least for the sake of playing games with 3D graphics), so video cards are still commonly used.

Power supply: the power supply is itself plugged into the wall socket for power. The motherboard and storage drives plug into the power supply for power. Other components, like the CPU, in turn get their power from the motherboard.


In order to control a component in your system, your operating system needs a driver, a piece of code particular to that make of device. For example, two different makes of video card need different drivers because they expect to be talked to in different ways. These drivers are usually installed properly when Windows itself is installed, but they can often be updated from the Internet much like a program. For example, for my ATI Radeon video card, I can download the latest driver from ATI’s website; it comes in the form of an installer program which I run to install it. For most devices, however, you needn’t worry about updating the drivers.

Installing an operating system

When your computer starts, it executes code found in a special chip on the motherboard called the BIOS. The job of this code is to simply look for an operating system to load, usually from a hard drive but possibly from a DVD or a flash drive. When the computer powers on, you can enter the BIOS configuration menu where you can choose which drive to load an operating system from. (The first screen you see when you turn on the computer should tell you which key to hit to enter the configuration menu. Usually this is F1 or DEL.)

To install an operating system on your hard drive, you need to run the installer included on the installation DVD by booting from that disc. Then simply answer the questions and follow the directions.