How to Build a Computer from Individual Components

Before starting anything, let's first think about the operating system that we will be installing on the computer when it's finished.

Why Linux

I've been using Ubuntu Linux for 5-6 years.
I started because I believe that free-open source software is a good thing for the planet.
I have nothing against Apple, except their pricing. They INNOVATE and make interesting products driving the public-tech product market forward.
Microsoft is another story. They do not innovate, only copy and use their monopoly to control the general public's access to technology. Their products most often don't work right, and require heavy computing resources. They are responsible for the computer Virus, which cannot exist on Linux or Mac (which is in fact Linux inside). So politically, I do not like to support Microsoft by using their stuff.
I am opposed to piracy. It is simply theft and I don't want to set an example for Félix or for anyone else that just because I can steal (i.e. pirate) I will. So either I download legal free software or I buy. The same for records, films, whatever. I don't steal milk at the super-market either. And yes, I do remember doing that as a poor student, simply I am no longer poor nor a student.
So I started working on Ubuntu 64bit Linux a long time ago, to help the planet. I believe that anyone who can should. Most of my IT friends feel the same and also work on making Linux and its components better.
Usability: for most things, Linux has either the same or equivalent tools. Some are better, some are different but as good, some are clearly inferior. But, since they are all free of charge, the cost/benefit is always better than MS or Apple (particularly Apple). If you are rich and don't care about price, then this is irrelevant. For example, my girlfriend knows nothing about computers, had Windows at work, has a Mac at home and uses my Linux machine here, with absolutely no problem.
Google and Linux: Google is a big supporter of open source and their tools work very well on Linux. Maybe you don't know the tool set, but if you go the way of Firefox, gmail and the associated tools, you see really no difference between Linux and anything else. By the way, using and supporting Firefox is very important for the free world. Never use other web browsers, no matter what platform, if you can avoid it.
That's it for the socio-political speech.

How to build a PC:

Decide on what processor you want, I suggest getting one about 2/3 of the way up the scale, that way you get a good long time before it becomes obsolete. If you don't play games, it may never become obsolete (on Linux). I suggest an INTEL processor, today.
CPU cooler: if your CPU did not come with a cooler, then you will need one. The only issue is the noise, a better cooler will be quieter. In general the INTEL cooler is good enough, if you want better, i.e. cooler+quieter go with a Zalman.
Decide what Motherboard goes with the CPU, I suggest only looking at ASUS motherboards. Decide what quality of sound you want since that is on the motherboard now-a-days. Also, you may want/need a firewire port. some motherboards have these on-board. Don't worry, you can always add more stuff on cards later, for example a 3 port firewire card costs $10, and is installed in 3 minutes by YOU! You may want to get WIFI on the motherboard if you intend to use the PC wirelessly, I run a wired connection to my home network since its easier and faster.
Select the graphics card. I suggest NVIDIA, not ATI. If you play high graphic demanding 3D games, like "Modern Warfare 2" for example, then you should look at getting the top end cards since the graphics power of your PC will soon become obsolete otherwise. PLEASE NOTE: I'm ONLY talking about BIG 3D GAMES. The graphics card is NOT a factor for film, photo, or anything else. believe me. If you don't play games, get a middle of the road NVIDIA card that is compatible with the CPU (processor). One thing, if you plan to get a modern screen in the next 5 years (which you should since screens blow out, yes, they only last 5-10 years max!), then be sure the card has a DVI or HDMI connector!
Next get memory, at least 4GB today. 1333 speed, Kingston is a reliable brand, or Corsair, or whatever they sell in the shop you use. If you get 2 bars, be sure to get the same ones.
Next is hard disk: get at least 1 TB for today's world.
DVD reader+burner: basically any one of the name brands Sony, Nec, Samsung. This costs $25.
Power supply: again better means quieter. You need at least 500W, but 750 or even 1000 if you went for a top end graphics card, or maybe even several cards if you're thinking of moving to Korea to become a professional gamer (a joke)...
Case: it's a mini-tower. Better cases have better cooling, easier access to the components and are more "elegant" if a PC can be so. $50-100 should be enough. Get one without a power supply, since you already got the power supply in the previous step.
Keyboard & Mouse: go for USB connected only, don't get ps/2 connectors as that is obsolete. Logitech is a reliable brand here.
Screen: go big, fast, and high res. 24inch, 5ms, 1920x1200. Any new screen you buy should have HDMI and/or DVI connector for digital signal from the pc. I have a Samsung T240, but that is already obsolete even if I only got it a few months ago!
That's it for the purchase of components.

As an example, here are the components I'm using for Félix's BIG GAMER:

CPU: INTEL 2 core i5-661 3.33GHz 4MB,
Cooler: Zalman CNPS 10X extreme
Motherboard: Asus P7P55D 7.1 Channel on-obard sound+firewire
Graphics Card: Nvidia GTX 275
Memory: 2 x 2Gb DDR3 1333MHz Kingston = 4GB total
Disk 1TB SATA2 disk with 32Mb cache
Samsung DVD reader/burner
Power Supply: OCZ ModXStream Pro 700W
Case: Antec Three-hundred.
Keyboard, Mouse, Screen: already had from previous PC's.

Preparation

Be very careful.
Ensure that you have Internet access on another PC, and that the parts shop will be open during the entire construction process.
Be even more careful!
Work on the floor, but not on carpet - avoid static electricity and losing parts.
Don't forget to BE VERY CAREFUL!

Assembly

Always follow motherboard instructions when doing this!

The Motherboard instructions will be your guide, follow them religiously.
Do not mount the motherboard into the case, yet.
Mount the CPU onto the motherboard
Mount the CPU Cooler onto the CPU+Motherboard, be careful to apply a regular light coat of heat transfer paste to the CPU, use a credit card or something plastic to spread it thin over 100% of the surface, with no excess,
Connect the CPU cooler fan wire to the correct plug on the motherboard,
Mount the back-plate that came with the motherboard onto the Case,
Mount the motherboard into the case (follow case instructions)
Mount the graphics card on an appropriate slot (probably the PCI-Express slot nearest the CPU) on the motherboard, follow motherboard and graphics card instructions, check on Internet if unsure, DO NOT USE BRUTE FORCE!
Mount the Disk into the case, you will see the 3.5inch bays, use a lower one, but not the bottom one, mounting screws come with DISK, avoid proximity to graphics card,
Mount the DVD drive into the case, use top 5.25inch bay,
Mount the power supply to the case,
Connect the number 1 Sata port on motherboard to the disk, cable supplied with motherboard,
Connect a power cable for the power supply to the disk, cable comes with power supply,
Connect the number 2 Sata port on motherboard to the DVD drive
Connect a power cable for the power supply to the DVD drive, you may be able to use a connector on the cable that went to the disk, if not use another cable.
Connect all the wires from the case front panel to the appropriate plugs on the mother board, read the instructions on the motherboard, if you have a ASUS motherboard, it's easier to connect all the wires to the supplied ASUS Q-connector, then plug that connector onto the motherboard,
Connect power cables to any fans that are built into the case,
Connect the specific power cables from the power supply to the motherboard. there could be as many as 3 of these,
Connect the specific power cables from the power supply to the graphics card. there could be none, one, or two, be sure to get this right,
Read the motherboard & graphics card instructions and see if there are any other cables to connect.
Read all the cable connection pages of the motherboard instructions and check off the ones that apply to you, not all will apply.
Try to organise the cables so it looks clean, use cable ties if necessary.
Now, go through all the motherboard instructions AGAIN, be sure that everything is right.
You may have finished the assembly.

First Power-Up

Before beginning, download Ubuntu and burn to a CD. You will use this for initial tests, no matter what operating system you want to install.
Do not close the case!
Connect Keyboard, mouse, screen, network (unless using WIFI) and mains plug.
Power on!
You should get some messages on the screen saying BIOS needs upgrade or configuration, etc. If possible continue by accepting default values (you will have to go back and configure the BIOS later...).
It will now say that boot device doesn't work. That's because the disk is both unformatted and does not contain an operating system.
Put the Ubuntu CD in the DVD drive and "hit any key".
Select English as language, then use F-keys to select correct keyboard key-map.
Highlight "run Ubuntu without installing" and hit return.
After 3-5 minutes you will see the Ubuntu desktop.
Everything should work, you should be able to surf the web using Firefox.
Look inside the PC case and be sure that ll the fans are turning and any LED's on the motherboard are the right color (see motherboard instructions).
This should be all 100% hunky-dorry. If not, try to figure out what's wrong. Shut down, disconnect mains & ensure that you are grounded (not charged with static electricity!) BEFORE touching anything in the Case.

Configure the BIOS

This part requires some knowledge and patience.
When all the previous steps are 100% correct. I stress 100%, not just more or less ok! Boot the PC and follow the screen instructions to enter Set-up.
Follow the motherboard instructions to configure the BIOS. I suggest keeping notes of every modification. I suggest not making more than 5 modifications without a test. That way it's easier to go back to a working config in case of failure to boot.
Most of the BIOS config is about optimisation so it's worth doing it once right when you are building the PC. You will probably never look at the BIOS set up again.
If there is a BIOS upgrade available, read its description to see if it applies to your components, don' just upgrade blindly. Usually, there is no way of going back after a BIOS upgrade....
When you have finished BIOS config, again boot using the Ubuntu disk as above and test to see that everything looks good!
If it does, you are now ready to install the Operating System.

Install the Operating System

This can take several hours due to the disk formatting step.
Be sure that the computer is connected to your network.
Use whatever Operating system you want preferably Linux, but Windows-7 is another option. Not Win/XP since that is obsolete.
Follow the instructions that appear on the screen when you boot from the operating system disk.
Voilà!

That was easy enough, right!