How To Build A Desktop Computer From Scratch and How To Choose Parts


This blog is intended to give you information about how to build a personal computer or a desktop PC. It will show you how to buy the components you need, and from the right sources, in order to build yourself the perfect desktop. I also introduce you to some basic concepts associated with what makes up a standard desktop computer. I also outline what’s required when making educated buying decisions when purchasing new hardware. The picture below will give you an idea of what is involved in the physical aspect of building a computer:

Figure 1.1 - Choosing the Right Components From the Right Source is the First Step in Building A  PC.
Figure 1.1 – Choosing the Right Components From the Right Source is the First Step in Building A PC.

The parts shown in Figure 1.1 above outline what components are necessary for building a desktop based personal computer. As you can see there are quite a few of the components required and while putting them together may seem a somewhat daunting prospect, this stage is actually relatively straightforward.

There are two other stages involved with this process – buying the parts and then having them assembled, then setting up a system to work with the parts chosen.

There are many factors to consider and any an mistakes at this stage can result in a computer system, that at best, is not what you really want and, at worst, simply won’t work.

For example the CPU may not be correctly installed or there may not be enough heat sink compound used causing it to overheat easily.  Or the memory modules may not be compatible with the motherboard chosen. Given the wide variety of motherboards available to choose from and memory form factors, it is easy to get this wrong.

The use of pictures helps illustrate what a fully assembled desktop computer looks like. Figure 1.2 shows an assembled PC:

Fully assembled parts in a desktop Personal computer.

After buying and choosing parts for the assembly of the desktop PC, the next steps involve configuring the system. This is done through changing different settings within the Basic Input / Output System (BIOS), formatting a hard disk drive and partitioning, installing the operating system (typically Windows 7 or 8 or Linux), and configuring device drivers to get hardware working with the operating system.

Choosing Computers Components And A System Type

Before you decide to take the Do It Yourself Route (DIY) and start spending your hard earned cash give some thoughts to the Pros and Cons of building versus buying. Also remember there are better reasons for buying from a store but you can give yourself more flexibility when you build your own system from scratch.

Store-Bought Versus Self Build

Here are some things to consider:

1. Time – Building your own computer from scratch is going to take a lot more time, then going into a store and purchasing a complete system already good to go straight out of the box. To make an educated buying decisions when shopping for parts you will need to figure out which suppliers are the cheapest which probably means you’ll have to deal with more than one.

  1. Effort – You have to build the PC set it up yourself, install components manually, and troubleshoot when problems arise.

  2. Aggravation – If the completed system does not work, then you have to take more time to troubleshoot problematic components. If it turns out that you have damaged a particular core component during installation, you will need to replace it with a working part, so be extra careful when installing hardware devices. Additionally, if you are unsure of how to fix a particular problem with the new system, you’ll may take it to a repair shop which involves additional costs for the time and labor if you choose to have the shop repair the problem. Buying from a big chain store such as a  Best Buy or Future Shop you will avoid this potential aggravation.

4. System Warranty – Purchasing from a big box chain gets you a warranty supplied by the store. Building your own PC from scratch gets you warranties, usually with the individual parts themselves. Buying from a store gives you added piece of mind.

Here are some advantages to building your own PC from scratch:

1. Cost – If you buy Original Equipment Manufacturer (OEM) parts and from the right source, your computer should be cheaper than purchasing a ready built PC. However, it is important to note that the difference might not be as much as you think and if saving money is your primary motive, you may find it is simply not worth the bother.

2. Component Warranties – If you decide to build your own PC, you will have the warranties supplied direct by a manufacturer often lifetime warranties for memory modules, and often 3 to 5 years for a hard disk drive. Other components house different warranties so its necessary to explore the different warranty types when you research before purchasing the parts required for the system build. Additionally, service from component manufacturers is usually much swifter and more reliable.

3. Quality – Most lower end market PC’s include parts of low quality. Typical examples are monitors and power supply units. Self builds allow you to choose good quality components that will give you a more reliable and longer lasting computer.

4. Features  – Buying a PC from a big box store you will most likely purchase parts that you don’t want or need. For example, the system may come with a huge graphics card but if you don’t play the latest high end video games or do 3-D intensive Auto Cad applications, you will be wasting some of your money. Bear this in mind, when you are choosing parts since you can choose the exact type of components that you want to include with adding any superfluous bells and whistles that you may never need or use in the system.

  1. Software – Usually all ready built computer systems comes with an operating system built in; building a PC from scratch requires you to license an operating system direct from the software vendor, which adds an additional costs to the system build. you can, however, use a pirate copy of an operating system, but it is not always wise because you won’t get the latest security patches when using a bootleg copy of Windows. Utilizing a version of Linux such as Ubuntu might be a free alternative to using an expensive Windows operating system.

Additionally, software that comes pre-installed on a factory built PC is out dated and of dubious quality. Much of it is usually useless to the buyer, and can be a waste of money. Building your own PC from scratch ensures you install only the software you want, whether it be freeware, shareware, or commercial based applications, you have the customization through the entire process.

Also, bear in mind that most manufacturers of ready built PC’s do not not supply an operating system disc, but rather supply an area on the hard drive devoted to restoring your PC to factory software settings in the event of a data emergency. If the image file is corrupted by a computer virus or other error you will have no way of restoring the operating system. While building your own PC there may be an additional expense involved with buying an operating system disc, you’ll have peace of mind knowing that if your operating system ever crashes, you can restore it through the operating system disc within a couple of hours. You can use as it as often as necessary to restore your operating system to working order.

What Do You Want From The Computer?

So you have made the decision to build a PC yourself completely from scratch. You now need to make a list of all the parts required. This is a vital process, as any mistakes here might mean your PC is not up to par with what you want it to do and upgrade decisions in the future might be more difficult complete.

Before making the list of parts you want make a list of what you want the computer to do. For example, what applications do you want to run on the PC, and do you intend to play high end video games or use resource intensive video applications such as CAD or Digital Video Editing utilities? Table 1.1 shown below the approximate hardware requirements for various types of software applications.

Disk Space
Operating System Windows 8

Windows 7

Windows Vista

1 GHz

1 GHz

1 GHz

1 GB

1 GB

1 GB

16 GB

16 GB

15 GB

Office Suite
Microsoft Office 2013 1 GHz 1 GB 3 GB
Desktop Publishing
Adobe In Design CS6 500 MHz 2 GB 2.6 GB
Graphics Editor
Paint Shop Photo Pro X5 1.5 GHz 1.5 GB 2 GB
Assassins Creed 3 2.4 GHz 2 GB 17 GB
Media Player
Real Networks Real Player 1.4 GHz 1 GB 400 MB
DVD Playback
Cyberlink Power DVD 13 2.4 GHz 512 GB 400 MB
CD/DVD Authoring
Roxio Creator NXT 1.6 Ghz 1 GB 3 GB

In regards to the CPU classification even the slowest model available on the market will be capable of handling virtually any single application. However, you must remember that in practice you will be running two or more applications simultaneously.

For example, if you plan to play Assassins Creed 3 on a Windows 8 PC, you will need a CPU rate at a minimum of 3.4 Ghz and at least 3 GB of memory. We say “minimum” because there will also be other applications running in the background that you are not aware of; these will be using the CPU and memory at the same time.

Retail Vs Oem Parts?

Once you have documented a list of your required components for a new system build, it is time to open your wallet. One of your very first decisions is to buy Retail or OEM parts.

Original Equipment Manufacturer (OEM):

As listed above, OEM is a term used to describe a company that manufacturers hardware to be marketed under another company’s brand name.Typically OEM products are sold unboxed and with no documentation or bundled software. Also, limited warranties are offered with OEM parts. All of this enables OEM products to be sold at a lower price, than traditional retail, as described in the next paragraph.

Retail Parts

Retail parts, on the other hand, will be packaged and supplied with user manuals, registration cards, and full warranties. Very often, a buyer will also get bundled software. Retail products are more than likely to be genuine articles. Just remember there are are many counterfeit products on the market.

Retail products will include things like a CPU heatsink and fan, whereas the OEM version does not include such a device. A hard drive labelled and sold through OEM does not come with a data interface cable; the retail version does include such a cable.

OEM Quality of Parts

Another crucial importance is that of quality. Retail parts have a higher quality more specically with silicone chips. All production lines, whatever the product, produce a number of sub-par items that nevertheless work. In literally every production run there will be some chips that are superior to others and these are the ones that are sold in the retail market, packaged and sold at retail prices. Inferior chips go to the OEM route. As a result, if you are looking to build a very high quality computer system, you will definitely need to buy retail boxed versions of said components.

Building On A Budget

If you are building for a budget, then buy OEM versions of parts. You will save a lot of money but bear in mind this could be at the expense of quality. You basically get what you pay, as with all things in life.

Sometimes people fall victim to overpaying for OEM versions of products. Computer stores in particular will try to sell you an OEM computer component at full retail price. If you are computer savy you’ll definitely not fall for this, but many people are caught out on this and end up paying the ful price for an incomplete and sometimes inferior product.

Where To Purchase Your Components / Parts

The final topic to be examined in this blog is to give you an idea of where to shop for your computer parts for a new system build. There are three main stops you should examine, Computer Stores, Mail Order, and The Internet.

Computer Stores

Buying your parts from a computer store is probably your safest and quickest option. If a particular component is defective you can simply return it and exchange it for a working one. However, it does mean getting off your backside, and does not offer the convenience afforded by mail order and Internet methods of shopping.

It is known that sales representatives in some of the general stores can be somewhat limited in their knowledge of computers. Any advice or opinions offered by these people should be taken with a grain of salt and checked out before you part with your cash. Alternatively, go to a reputable store where the staff are known to be technical experts.

There is also the risk of you paying full price for out-dated items. While to be fair, this can also happen with mail order and Internet companies, in practice, it is less likely as these companies exist by undercutting the big computer stores and will take every opportunity to do so.

You will pay the highest price for your components in computer stores, as they have high overheads to cover.

Mail Order

Mail order is a convenient alternative to buying from computer stores. It allows the buyer to compare prices without having to trudge from one store to another. Additionally, you do not have to keep fending off pushy sales staff.

You will find that a mail order catalog has a much wider range of products than you would find in any computer store.

Sales staff tend to be more knowledgeable about the products that are selling and will usualy give you better advice than you would get in a store.

Prices will be lower than store prices and this is mail order’s main advantage.

Disadvantages include time and distance. The company’s headquarters could be several hundred miles away, so if there is a problem you cannot just nip down and get it sorted out immediately. Delivery is done by courier and it is quite common for delivered goods to arrive in a damaged condition. This means delays while the item is reshipped.

The Internet

The Internet has become a real asset to those who build and upgrade PC’s. Not only can you buy parts at the lowest price online, but you can also get a tremendous amount of information to helpo you make informed buying deciions.

There are sites devoted to all the major parts of a computer system. These offer information such as technical details, troubleshooting, installation and buying guides, etc. If you are looking for detailed specifications on a particular product vists the manufacturer’s website, all the major manufacturers are online.

Also online are the major computer and computer parts retailers. Their online prices are lower than in their retail outlets

Parts You Will Need For A New Desktop Computer Build

The following is a list of the hardware components you will need to build a basic computer system:

  • Monitor
  • System case
  • Power supply unit (PSU)
  • Motherbaord
  • Central processing unit (CPU)
  • Memory (RAM)
  • Hard disk drive (HDD)
  • Video card
  • Sound card
  • DVD or Blu-Ray drive
  • Keyboard
  • Mouse
  • Speakers

Tools You Will Need For Assembly

There are very little tools required to actually build a PC. The following is all you are likely to need:


One medium size cross-head screwdriver for screwing the motherboiard into place and securing the drive units and expansion cards into the case.


For cutting cable ties to length. You will need these to bundle up the internal cables in a neat fashion, so they do not interfere with the airflow in the case. You will also need a supply of cable ties. These are available from any computer store.

Electro-Static Wrist Strap

This item is not essential but highly recommended. The static electricity in your body is a killer for the PC’s circuit boards, this applies particular to the memory modules. Alternatively, you can buy a pair of close fitting rubber gloves such as those used by surgeons. This will serve the same purpose.

Congratulations! You now have a basic understanding of how to shop for parts, what parts to choose for a new system build, and hopefully you have decided to move forward and build a desktop computer completely from scratch. Watch my other blogs series’ for more information about specific components that comprise a standard personal computer.


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