The Basics: Desktop Computers
First-time computer buyers used to buy desktops for menial tasks like word processing, checking e-mail and Internet browsing, or managing checkbooks and recipes. It's become much simpler for the consumer to use their new computer as a multimedia machine, managing photos, music, and even movies with a DVD drive.
Dedicated game players will likely want a faster computer with more memory, but most entry-level computers (at entry-level prices) have enough speed, memory and storage to handle all these tasks. Powerful computers are becoming more affordable, and many budget models will let you burn CDs, run sophisticated operating systems and play the latest video games right out of the box.
It's never been easier or less expensive to buy a state-of-the-art personal computer. It wasn't long ago that computer manufacturers were striving to come up with a sub-$1,000 PC. For a while, there were even stripped-down, basic machines on the market for less than $500, though the poor profit margins on these systems have pretty much forced them from the market.
The winner here is, of course, you. Options for the PC buyer abound like never before. Keep in mind that "basic" is a very relative term. Even the most basic PCs these days provide features and performance that are astonishing.
How to Shop
Before you decide anything, decide how much you can spend. After that, take a look at what you want out of your computer -- is this the first home computer for you and your family? Will this be for your college-bound son or daughter for the next four years? Are you anticipating the newest game releases? The tasks you want to accomplish will dictate the specifications you need in your new computer.
Your choices begin just with the shape of the computer itself. For a cramped office or living space, small-form-factor (or SFF) computers are an easy solution. Their main disadvantage is that with a small cabinet, there are less expansion slots, and therefore less room for upgrading. There's still plenty of ports, however, and it's a perfect temporary solution for dorm rooms and LAN-party gamers, sometimes even equipped with handles for easy transport.
If space isn't a concern, a mid- or full-tower case ensures that you'll have the room to upgrade your computer for years to come. If space is really limited, the all-in-one case is a desktop built into a flat-panel monitor. It's just as limiting when it comes to expansion slots, but it takes up little to no space (and is pretty cool-looking).
Your options for processors can be confusing, with competition between AMD, Intel and Apple making it hard to tell which processor is best. Pay attention to the speed of the processor, measured in gigahertz (GHz), to know what you're paying for. Even budget-priced desktops should run near 1.4 GHz, and over 2 GHz if you have more money to spend.
If your budget is tight, scaling back on the processor might be the best way to lower the cost. The processor is the brain of your computer, and dictates how fast your applications will run, but most programs run just fine without the high clock speeds at the top of the market now.
The PC's main memory, where its operating system and programs are run, is called RAM (random access memory). RAM is relatively inexpensive, and operating systems and applications are becoming ever more memory-hungry. The minimum amount of RAM you should get is 256MB, but many PCs offer 512MB or even 1GB and over. More RAM is always better, as your applications will generally run faster with more RAM available, and Windows XP runs best on at least 512MB.
New computers often feature graphics cards that are "integrated," meaning they draw on the same memory as the rest of your applications to generate graphics. For most users, this is fine.
Those who need a desktop for graphically-intensive business programs, video editing, or the newest in video games, a discrete video card is better. These cards have their own pool of memory to draw from. The lion's share of upscale video cards are manufactured by ATI or NVIDIA, so look for one of those names if your graphics card is built-in to your new computer, and aim for the highest amount of discrete RAM that's affordable for you.
Traditional floppy drives are often optional features on new computers. Any manner of ROM drive is available for your desktop. Combination drives are included with many new models, able to read from CD and DVD, burn media to CD, or, if dealing with large amounts of files, burn to DVD and Double Layer DVD to exchange and transport large files and multimedia files. Consider how many media files you'll be using, and how large, and decide whether your computer will be doubling as a DVD player on occasion before making your choice.
Many desktops come with ports for both dial-up modem and an Ethernet connection already built-in to the back of your computer, so your computer is ready to connect anywhere. Ethernet cards are required for broadband Internet connections or connecting to networks (like at a college campus), so know beforehand how you'll be connected.
If you have more than one computer at home, adding wireless cards to each is a handy solution for home networking. Also behind your desktop, USB ports will allow you to connect to peripherals like digital cameras, portable music players and other devices to transfer files back and forth. Many desktops have FireWire ports, and while that technology isn't as ubiquitous as USB 2.0, you can transfer data back and forth even faster if your peripheral is FireWire-ready.
You should look for at least four USB slots, able to accommodate constant peripherals like printers and keyboards, and have room for recreational ones like digital cameras and music devices. Some models have USB ports in the front as well, making connections even more convenient.
The average desktop warranty will last one year for parts and labor. Some companies provide on-site service, and will send a technician to your home if a problem can't be fixed over the phone or online. Others require dropping it off at a local service center or shipping it directly to the manufacturer. If that's the case, find out who pays for shipping.
Many companies offer extensions on the warranty, sometimes up to three additional years, for an added cost. The decision of adding onto the warranty rests with you. Deciding factors can include: whether you are comfortable making repairs yourself (or letting a friend or relative do so), as well as how much you spent on the system.
Glossary
Hard disk
Optical disk
Processor
RAM
from: http://products.howstuffworks.com/desktop-computers-buying-guide.htm
