Components

Computer components and their primary functions

CPU (Central Processing Unit)

This is the most important part. It's speed is measured in Hertz (cycles per second). The greater the speed, the faster the computation. (A gigahertz = 1,000 megahertz. A megahertz = 1,000 kilohertz. A kilohertz = 1,000 hertz.) Intel and AMD are the 2 major manufacturers of CPU's. Intel chips are pentium, celeron, and centrino. AMD chips are often referred to as Athlon. Computers using AMD processors are usually priced lower. They run fast but put out more heat (& consume more battery power) so adequate cooling is essential. (A concern for portable computers when they're on your laps or on battery power.)

Pentium processors (by Intel) are generally considered the most reliable chips and usually cost more. Centrino processors (aka P-mobile) are designed especially for portable computers. They consume less power and run cooler. Celeron processors are a less expensive version of Pentium chips. They're designed to compete (pricewise) with AMD chips.

Motherboard

This is the main board where all the components are attached to. It's ability to route signal rapidly between the various components is known as the buss speed and measured in hertz. Each motherboard is designed to be compatible with only a few CPU models so your choice of CPU dictates which motherboard is used. Upgrading a CPU later often requires purchasing a new motherboard as well, which make this option expensive. The buss speed is seldom a choke point because it's equitable with the CPU speed.

RAM (Random Access Memory) chips

The CPU stores data here temporarily while it's calculating. More RAM means less time wasted retrieving data from the permanent storage. Buying more RAM is the most cost effective way to speed up your computer. Most computers are sold with limited RAM to keep the price down. Computer retailers know that shoppers focus on CPU speed and often overlook RAM capacity because it's easy to add RAM later. Being RAM deficient, however, is like buying a big Jacuzzi with a small heater. RAM chips are measured in bytes and come in several varieties. Make sure you buy the right one for your motherboard type. Having plenty of RAM capacity will take full advantage of that fast CPU you paid for.

HD (Hard Drive)

The hard drive is where data is stored in your computer. Every program installed and every file you create are written in your hard drive. When the CPU needs specific data to perform the task you want, it retrieves those data from the HD and stores them temporarily in the RAM chips. If it needs more, it will swap out and manage the needed data according to the RAM space available. The more often it has to retrieve data, the longer it takes to complete the task. HD capacity is measured in bytes for space and RPM (Revolution Per Minute) for speed. The faster it spins, the faster data can be read and/or written. If you need more space, hard drives can be added. Both internal and external HD's are available. Adding external HD is easy and reasonably cheap.

Peripherals

These are components that perform specific tasks in your computer. Most are now integrated into the motherboard but add on units can be installed as upgrades. All motherboards have available slots to accommodate these cards. Some boards have more available slots than others.
Sound card: process sound ranging from basic quality to state of the art audio.

Video card: process what you see on the screen ranging from basic quality to extreme demands of games.

Ethernet card: process networking functions and signals so computers can be connected to each other.

Modem: process phone line signal and convert them to signals that computer can process.

USB ports: receptacles for connecting external devices to your computer, i.e., printer, external HD. etc.

DVD/CD drives: optical devices for reading/writing CD and/or DVD, usually installed inside your computer.

Other peripherals include TV tuner card, memory/flash media reader, floppy drive. This list is still growing.

Save all CD/DVD's that came with your computer and programs you added. You'll need them if you ever have to install them after a system failure. Only data files are backed up each time you do a computer back up. Programs are not included in most back ups and must be reinstalled after system failure.