• A set of screwdrivers (small, large, slot, Phillips), or a PC Tool Kit
• An anti-static wrist strap
• Needle-nosed pliers
• CPU (processor)
• CPU cooling fan and heat sink
• Sound Card
• Motherboard
• One or more hard drives
• Graphics card
• One or more RAM DIMMs (Memory modules)
• An operating system

1. Before you dive in…
Before you start the job, you have to take inventory of your parts. It does little good to begin your build when you don't have everything you need. Once you've determined you have everything you need, it's time to start! Make sure you have plenty of working room and a few hours to proceed with minimal interruption. Please note that carpeting represents some real dangers to your computer. The carpeted surface has the potential to create static electricity that can fry your components. An inexpensive antistatic wrist strap (they are often priced at less than 6 bucks) is the perfect preventive measure if you have no alternative to working on carpet. Remember, a bare floor is always the best place to build your system. Now, grab hold of a good set of screwdrivers, a pair of needle-nose pliers, and an antistatic wrist strap, and make sure you're wearing your antistatic wrist strap (it does you no good at all if you don't wear it!) Finally, download the latest drivers from the vendors' Web sites for each component you'll be installing, and copy them to a CD to avoid headaches later on; the drivers that come in product boxes are often several versions out of date.

2. Dive in!…Installing the Motherboard
Here comes the fun part! Installing the motherboard. First, take the board out of its packaging and put it on top of the antistatic bag it came in. Remember, you always want to safeguard your components from potentially hazardous static electricity. Before you secure the mobo onto the PC case, you should install the processor, heat sink and the memory modules on it. If you aren't sure which socket is which, or what goes where, consult your motherboard's user manual for guidance. User manuals are extremely helpful, easy to read and include illustrations. First, lift the lever on the processor socket so you can install the CPU. Carefully line up the pins and place the chip in its socket; it will fit only when oriented the proper way. An arrow or a missing pin on one corner of the chip will show you how to line things up. Lower the lever to lock the CPU into place.

Next, follow the manufacturer's directions to install the heat sink and the fan that will cool the processor. If you bought an OEM CPU and a separate heat sink, you may need to spread a thin layer of the thermal grease that came with the heat sink over the chip to ensure proper transfer of heat (some heat sinks come with this grease already applied). Attaching the clip that holds the heat sink in place may require a fair amount of force. Again, the instructions that came with the heat sink will show you how to know whether you've fitted it correctly. Plug the fan's power connector into the proper connector on the motherboard.

TECHNIQUE: This part can get a little tricky. But stick with it and you will have no trouble at all. In order to install the memory modules, insert them into the proper sockets and push down firmly but evenly until the clips on both sides of the socket pop into place. If your motherboard supports dual-channel memory, consult the user manual to determine which pairs of RAM sockets you should use. The motherboard and the CPU are the brain and nerve center of your PC, so selecting these components might just be the most important decision you'll make.

TIP: Choose the processor first: Despite running at slower clock speeds than their Intel-based rivals, AMD-based systems have maintained a significant performance lead in documented benchmark testing for a while now. At the high end, Athlon 64 FX CPUs are the fastest around. There are positive and negatives to each CPU, so do a thorough investigation before making your buying decision. Remember, an informed buyer has a much higher probability of being a satisfied one.

TIP: Choose the motherboard after selecting the processor: The processor you choose usually determines which motherboard you select: Motherboards are designed to work with specific CPUs, indicated by the type of socket that the processor fits into. Socket A, Socket 939, and Socket 940 are designed to work with Athlon processors, while Socket 478 and the new LGA socket 775 are for Intel CPUs. Many dealers offer bundles consisting of a processor, a motherboard, and memory; these can be a good way to save some money. The system chip set (the chips that pass data between the peripherals and the CPU) is the other component that differs among motherboards; it determines which integrated components (graphics, sound, Ethernet, etc.) will be included. Though integrated graphics aren't generally as good as dedicated cards, they're usually adequate for simple tasks.

3. Placing the Motherboard into YourCase
First, a word about cases. The right one can make working with your system a dream, but picking the wrong one will come back to haunt you. Though you can find a case plus power supply for less than $50, we recommend that you invest a bit more to obtain a case that will last through many upgrades and that you'll enjoy looking at.

Case Formfactor: Most cases and motherboards use the ATX form factor--a set of design standards that specify things such as the size of the motherboard and the connectors on the power supply. It's critical that your motherboard match the form factor of your case. Be aware of other standards--for example, Shuttle-style cube-shaped systems that come with their own custom motherboard. Check carefully and note the formfactor when shopping.

Case Construction: Steel cases weigh more than aluminum ones, they cost less, and they muffle the noise from components such as hard drives better than aluminum cases do. On the other hand, aluminum boxes tend to be more stylish, and they are certainly easier to carry around.

Case Convenience: Even the best-looking case will seem ugly if installing your components becomes a pain. Look for helpful features like a removable motherboard tray, tool-less drive carriers, and multiple fan locations for cooling the system.

TIP: Does this PC case include a power supply? Cheaper cases often come with cut-rate power supplies that may not be up to the task of powering a high-end PC. Some expensive cases don't come with a power supply, which lets you choose your own. If you've added a lot of new components to your PC, you may be overtaxing your existing power supply, so look at getting a bigger, better one. Power supplies can cause problems--including random crashes or even component failure--if they are asked to produce more power than they are designed to generate. Reputable manufacturers will typically include a chart of acceptable components.

Memory: The More, The Merrier.
Because it's an easy upgrade to perform and can significantly improve performance, boosting a PC's RAM is one of the most popular hardware enhancements people undertake. This 5-minute procedure can let you keep more programs open, accelerate memory-hungry graphics programs and games dramatically, and sharpen your PC's responsiveness. The memory modules that most recent systems accept are 184-pin DDR DIMMs of varying speeds, such as DDR333 or DDR400; the number describes the RAM's clock speed. You'll sometimes see memory referred to by the bandwidth it offers, such as PC2700 (DDR333) or PC3200 (DDR400). The type you should buy depends on the motherboard and processor you choose: For best performance, opt for the fastest type of memory module that works with both. A new type of memory (called DDR2) offers even speedier performance, but this can be used only on new systems equipped with the latest Intel chip sets.

TIP: Get at least a gigabyte: Sure, you can save money by installing less, but 1GB of RAM puts you comfortably above the point at which most speed gains occur, and it should enable you to run the most demanding applications and increase the speed of your system when you keep more than one program open at a time.

TIP: Opt for dual-channel if possible: If your motherboard supports it, use dual-channel memory. This type of memory boosts performance by increasing the speed at which data can be read and written. But for it to work, you have to install matched RAM modules in pairs. Some early dual-channel boards came with only three RAM sockets. If two of those sockets are already filled, you must either upgrade with a single DIMM (and lose some performance) or replace your two existing DIMMs.

TECHNIQUE: Some PC cases have a removable motherboard tray. If yours does, remove the screws holding it in place and pull it out of the case. Note the pattern of the holes in your motherboard, and screw brass standoffs into the motherboard tray or into the PC case in the correct locations. Check the layout of the sockets on the motherboard, and confirm that the ports on your motherboard's back panel match the holes on the I/O shield that is installed in your case. If necessary, remove the old I/O shield by tapping it firmly a few times with the butt-end of a screwdriver, and then replace it with the shield that came with the new motherboard.

TECHNIQUE: Carefully position the motherboard on top of the brass standoffs, line up all the holes, and use the screws that accompanied the case to fasten down the motherboard. If you are using a removable tray in your system, slide the tray and motherboard back into the case and then secure the tray.

4. Connecting The Color-Coded Power Cables.
Obviously, making the proper connections is crucial to your successful PC system build. Fortunately, manufacturers now provide color-coded power cables to make the job easy. First, plug the large ATX power connector for your power supply into the matching port on your motherboard. Next, locate the smaller, square processor power connector ( you can't miss it - it's the one sprouting the yellow and black wires) and attach it to the motherboard. Note: your connector is usually located near the processor. Now it's time to get out your motherboard user manual and find the description about front-panel connectors. Be forewarned - you're going to be doing work now that requires attention to detail and can be quite frustrating if you don't go into it with the right attitude. Okay, now that we've warned you, attach each of the tiny leads from the power and reset switches, the hard-disk activity lights, the PC speaker, and any front-panel USB and FireWire ports to the corresponding pin on your motherboard. If you have to, don't be afraid to use your needle-nose pliers.

5. Install the Video Card (and test it.)
Close your eyes and imagine the incredible video you're going to see once you're brand new, custom-built PC is up and running. Okay, open them up again and let's get to work. It's time to install the video card so you can see those great images. First, remove the backplane cover for your AGP or PCI Express X16 slot, install the graphics board in that slot, and then secure the card with a screw. Some graphics boards require a dedicated connection to your PC's power supply. If yours does, you should plug in the correct power connector now. Connect a keyboard, mouse, monitor, and power cable to your computer and turn it on. If the internal fans begin to whir, the system beeps, and you see the machine starting to boot, power down (by holding the power button for 5 seconds) and continue building. If nothing happens, back up a step and recheck all of your connections. Make sure that both the processor and the memory are properly seated, and recheck those minuscule leads connecting the motherboard to the power and reset switches.

Graphics boards have become the high fashion of computing. As new, super fast graphics chips emerge every six months, trendy techsters don't want to get caught checking out the latest 3D game with a board that's "so last season." But you needn't spend a fortune to get good performance.

TIP: Don't pay for features you don't need: At the high end ATI and nVidia have been flirting with designer pricing, as loaded enthusiast parts go for upward of $500. At those prices, only the most hard-core gamers will pay to keep up with the latest styles; but even if your needs are relatively modest, you can easily find an affordable board that boosts your PC's 3D graphics speed. If you're doing some light photo-editing, gaming or just surging the web, a $50 or $75 video card is more than adequate. Look for models that have 64MB or 128MB of dedicated memory.

TIP: Make sure you get the features you want: Most graphics boards today let you connect a second display to your PC. If you'd like to use your PC to record TV, a board with an integrated TV tuner (like the ATI All-In-Wonder line) is a good choice. EVGA (www.evga.com) makes a competing set of TV tuner-equipped graphics boards based on nVidia's Personal Cinema chip set.

TIP: PCI Express--the next generation of video display: The latest graphics cards now use PCI Express, an improved version of the AGP slot on most PCs. Our tests of new PCI Express graphics cards detected no significant speed gains as a result of upgrading from AGP to PCI Express, though that will surely change as graphics chip speeds increase and as games get more complex.

Gamers Agree: Don't Skimp On The Video Card.
An integrated graphics processor is like a suit bought at Wal-Mart: It does the job, but it doesn't look great. The PC World Test Center tested a PC with integrated graphics on a number of 3D games, and found them virtually unplayable. But when we installed a $220 Radeon 9800 Pro graphics card, the games ran much faster. This upgrade isn't difficult. First, find out who makes the graphics chip you already use: Right-click your desktop, choose Properties, and select the Settings tab. Your graphics board will be listed under 'Display'. All graphics cards based on chips from NVidia now use the same set of drivers, so if you're upgrading from one NVidia-based card to another, download and install the latest NVidia drivers. The same is true for ATI-based boards. If your new card switches graphics chip brands, you should uninstall the graphics drivers before you upgrade.

Shut down your PC, unplug it, and open the case. Remove the old graphics board (if any), insert the new board into its slot, and secure it with a screw. Plug your PC back in, turn it on, and follow the manufacturer's directions to set up the new graphics board.

6. Installing the Drives
Now it's time to install your drives. It's an easy process, but again requires some attention to detail. Gather up all your drives. Collect the hard disk, the optical drives, and the floppy drives, but be certain to make any necessary changes to jumpers on the drives before mounting them in the case. A two-drive system (one or two SATA hard drives, plus one parallel ATA optical drive, for example) is easy to set up; the SATA drives are jumper less, and the optical drive can be set as master on its own parallel ATA channel. Many cases use removable drive rails or cages to house drives. Use the included screws to attach your drives to the rails or cage, and slide them into the case. For externally accessible drives such as a DVD recorder, you can save time by installing one drive rail and sliding the drive in for a test fitting to make sure that its front is flush with the case.

When the drives are installed, connect power and data cables to each one. Parallel ATA drives use wide, flat data cables that can be installed only in the correct way. Floppy drives use a similar but smaller cable; SATA drives use a thin, 1cm-wide data cable. SATA drives use a new type of power connector that many power supplies don't come with. Fortunately, many motherboards ship with adapters for converting a standard four-pin power connector to a SATA power connector. Some drives ship with both the older connector and the SATA power connector. In that case, use one power connector or the other, but not both. The capacity of hard drives continues to increase: You can now hold 400GB of data on a single drive, which is great news for digital media pack rats and video editors. But though you don't have to compromise on the drive's size, you still have a few choices to make when picking a hard disk.

Upgrade Option: RAID RAID, which stands for Redundant Array of Independent Disks, lets you use multiple hard drives to boost disk speed or to keep a mirrored backup of your data in case a drive fails. Either setup requires multiple identical drives, and configuring them calls for a little mental gymnastics. An increasing number of systems on our Top 15 Desktop PCs chart use a configuration called RAID 0, which can significantly increase system speeds for data reading and writing. If you would like to try it, first select a pair of drives that match the storage capacity you want. With 120GB hard drives available for under $90 and with RAID support included on most new motherboards, RAID can be a great value.

Upgrade Option: Serial ATA; Even bargain-priced motherboards now include SATA support, and going with an SATA drive will make your system easier to set up and your drive simpler to move to a future PC when the time comes. If you're looking to boost the storage capacity of an older PC, the answer gets more complex: To use a SATA drive, you must add a SATA controller card. Many SATA controller cards give you the option of adding RAID support to your system, too. Is it worth it? Well, if you do a great many tasks that involve a lot of disk access (such as video editing), it can be. But otherwise, just add a second parallel ATA drive.

Transferring Your Data
When you add a new hard drive to an older PC, it's almost always faster than the drive already in use. But simply installing the new drive on your PC will strand your OS on the slower drive, forfeiting some benefits of upgrading. Make sure you use the new, faster, hard drive as your boot drive. Retail hard-drive upgrade kits usually come with software that you can use to clone your existing drive to the new one, making the faster drive your boot drive. But before you do this, pause and consider whether it may be time to start over. Over time Windows fills up with discarded files, drivers, and other crud. Adding a hard drive can be just the excuse you need to reinstall Windows from the system restore CD that came with your PC.

CD, CD-RW And DVD
Whether you upgrade or build a new PC, adding a fast optical drive can increase its flexibility. And even if you're on a budget, drives that read and burn any format under the sun won't break the bank.

TIP: Get An "All-In-One" Drive: No need to worry about whether your drive supports DVD+RW or DVD-RW-for around $90 you can get an 8X DVD combination drive that writes to all major formats of rewritable DVD. Burn DVD+R and -R discs at 8X, both rewritable DVD formats at 4X, CD-Rs at 40X, and CD-RWs at 24X. You'd save only about $40 by going with a simple CD-RW/DVD-ROM combo drive, so you get more value with a DVD burner that does it all.

TIP: Burn Speed Even no-longer-top-of-the-line 8X DVD burners can write an entire disc in less than 10 minutes, and CD burning speeds these days are sufficiently fast at the upper end that the difference between 48X and 52X is negligible. Consequently, if you're on a budget, there's no reason to pay a premium for a 12X or 16X DVD burner or to insist on buying the fastest CD-RW drive you can find.

TIP: Do not use bulky "Ribbon" cables: The flat, wide ribbon cables that Parallel ATA drives use to carry data can restrict airflow inside your case, robbing your system of valuable cooling; and functionality aside, they're just plain ugly. Rounded data cables available at your local PC store look much nicer, and they don't impede airflow.

TIP: The Storage Secret: Dual-Layer DVD "DL" What's 12 centimeters in diameter and can hold 8.5GB of data? A dual-layer DVD disc, that's what. Most stand-alone DVD players can play the dual-layer discs that these drives burn, boosting the amount of video that will fit on one disc. You'll pay a small price premium for early dual-layer drives, however, and compatible media may be hard to find at first. In addition, writing to dual-layer discs is slower than writing to single-layer ones--2.4X for the former, as opposed to 8X, 12X, or 16X for the latter. We recommend waiting until the prices of drives and media fall before switching to dual-layer unless you need the extra storage space.

TIP: One Cable, Two Drives: So-Called "Master And Slave."
Adding a drive to an older PC isn't always a question of simply plugging it in. Most older PCs use parallel ATA technology, where two drives share one cable (this is referred to as a channel; most PCs come with at least two IDE channels for a maximum of four drives). Setting a jumper designates each drive as either a master or a slave, which permits a single cable to connect two drives to one IDE channel. The jumper settings for each designation are usually labeled on the drive itself. A few simple rules should guide your configuration choices. If possible, each drive should sit on its own IDE channel configured as a master drive. If you have two drives on one channel, always make the faster drive the master drive. For example, suppose that you wanted to add a second hard drive and a DVD burner to a PC equipped with one hard drive and one CD-RW drive. In that case, you would want to set the new, faster hard drive as master on the primary IDE channel. Your older hard drive should be the slave drive on the primary channel, with the two optical drives as master and slave on the secondary channel.

7. Install the Add-In Cards
Take another deep breath. You're getting close to the end. Perhaps you might take a short break, check out all the great things you've done and get ready for the home stretch. Now, for each add-in card, you must choose a free PCI slot. Next, remove its backplane cover to allow access from the rear of the case. Carefully position the card above the slot, and press down firmly to seat the card. Secure the card with a screw. Many motherboards have additional sound connectors or ports housed on small add-in boards. Some of these plug into slots on the motherboard; others screw into the back of the case in place of slot covers. Usually the additional ports are not essential to your PC's operation. For example, if you install a sound card, you do not need connectors to the motherboard's built-in sound chip. Although we may sound like a broken record in saying this, once again check your motherboard manual to determine what each of these boards does.

8. Turn It On (and check your PC Set up)
Having fun yet? Of course you are. It's time to get on with the business of turning on your system and checking out your PC set up. So plug in the keyboard, mouse, and monitor to the appropriate ports on the back of the PC. Plug the power cord back in, and turn the machine on. Enter your PC's BIOS setup screen by pressing the indicated key (often Delete) as the machine boots. Menu options will vary from board to board, but they share the same general categories. Set the date and time, and then look for a setting that deals with PC health status and monitoring. That choice should bring up a screen showing processor and case temperature. Watch the processor temperature for a few minutes. It should stabilize at a level between 30°C and 50°C. If it keeps increasing, your heat sink probably isn't installed properly. Power down and check to see whether the heat sink is securely attached and making good contact with the processor. Next, find the section of the BIOS setup that determines the order in which your machine checks drives and devices for one it can boot from. Set CD-ROM to the highest priority so that your machine will boot from the Windows installation CD.

9. Installing the Operating System
Now you are just two simple steps away from running your very own custom-built personal computer. All that's left is to install the operating system and then update your drivers and install the programs. First, place the Windows installation CD in your optical drive, reboot the PC, and allow the system to boot off the disc. Windows setup should begin. Early in the process, Windows will ask you whether you need to install a third-party SCSI or RAID driver. If you're using a RAID setup, press F6 when this message appears; then insert the floppy containing the appropriate driver when it is requested. If your machine hangs while installing Windows, there may be a problem with one of the components. Try removing everything except the core components (motherboard, processor, one memory module, and hard drives); then, once you've successfully installed Windows, begin reinstalling each component one by one to isolate the source of the problem.

10. Last, But NOT Least: Update Drivers and Install Programs
Once you've got Windows up and running, the last step in this exciting, build-it-your-self process is to update your hardware drivers. This is not an optional procedure - you MUST do it. Insert the CD with the latest drivers (from step 1) and install them, starting with those for the motherboard and graphics card and then moving on to less critical ones like mouse and sound card drivers. (Windows comes with basic drivers to get you up and running.) Several reboots later, you should have a shiny new PC! Next, get your network connection up and running, install a firewall, and download the latest Windows patches. Finally, make sure that everything runs okay, and then back up your system. That way you'll have a clean, current image of Windows to go back to if serious trouble arises in the future.You're installing. If these steps check out and you're still experiencing spontaneous reboots, your problem may be one of the following situations.

Overclocking: We do not recommend overclocking. Memory Timing: The fix? Go into your BIOS and set your memory on "Auto" or at a more conservative setting and see if the reboot problem goes away. Outdated BIOS: Make sure you have the latest BIOS for your board. You can determine if your CPU is supported by browsing the BIOS updates of the motherboard's manufacturer. If you're running a Pentium 4 Extreme Edition and notice that it's only supported with the latest BIOS updates, you may have located the problem! Inadequate Power: If you've made significant component upgrades---with the exception of the power supply---your power supply may be overstressed or failing due to heat or age. Finally, if you've migrated your OS and other files from machine to machine to machine, it may be time for a clean install.