NELSON ANJERE:
BUILDUP CONTENT FOR PROGRAMMERS AND SOFTWARE ENGINEERS.
TROUBLESHOOTING YOUR MACHINE
Its good to have knowledge about how to trouble shoot your machine best on the work you do to avoid inconvenience or reliance on expert.To know this is very easy but under one condition....you must have passion to words it or else you might miss the point.Lets first look at the basic computer hardware so as to familiarize ourselves.
A typical desktop computer consists of a computer system unit, a keyboard, a mouse, and a monitor. The computer system unit is the enclosure for all the other main interior components of a computer. It is also called the computer case, computer chassis, or computer tower. Cases are typically made of steel or aluminum, but plastic can also be used. While most computer cases are rather dull, black, metal boxes, some manufacturers try to give the unit some flair with color and special design elements.
FUNCTIONS
The primary function of the computer system unit is to hold all the
other components together and protect the sensitive electronic parts
from the outside elements. A typical computer case is also large enough
to allow for upgrades, such as adding a second hard drive or a
higher-quality video card. It is relatively easy to open up a computer
system unit to replace parts and install upgrades. In contrast, it is
quite difficult to open up a laptop computer, which is not designed with
replacements and upgrades in mind. In most computer system units, the front side contains the elements a user needs frequently, such as the power button, an optical disk drive, an audio outlet for a pair of headphones, and a number of USB connections. The back side contains all other connections - for power, monitor, keyboard, mouse, Internet connection, and any other peripheral devices. There are typically more connections than the minimum necessary to allow for expansion.
COMPONENTS FOUND ON THE MOTHERBOARD
In this particular example, the motherboard is placed vertically, which is quite common. One side of the motherboard is accessible from the back of the computer case - this includes the various connectors for input and output devices as well as expansion slots for additional peripherals. The motherboard also contains the central processing unit (CPU), although it can be difficult to see. A large fan is often placed on top of the CPU to avoid overheating. The motherboard also contains the main memory of the computer.
The motherboard Is the basis of your computer. It's the first component installed in the system unit, and it holds all of the circuitry that ties the functions of the computer components together.
Central Processing Unit
The motherboard and circuitry need to have power.
There is a power box included with your system unit, and you'll see a
cord coming out of the back of your computer for that. 
The central processing unit,
or the brains of the computer, sits on the motherboard and does
actually have its own cooling fan. The processors now are so fast they
need to be cooled down. All the instructions you give the computer -
like a click of a mouse - go through the CPU, which processes in
billions of cycles per second. Commonly installed processors have
quad-cores, or four separate processors in one component. There are
six-core and eight-core available, and the more advanced the technology
the higher the cost. That's one of the choices you might need to make.
Memory, Cache, RAM, ROM
ROM, or read-only memory, is located here as well. This is a permanent, or non-volatile, memory. As soon as you turn on your computer, the start-up instructions that are stored in ROM begin to execute. Even when you turn it off, the instructions stored in ROM remain. So if you have a machine that runs Windows, as soon as you hit the power-up button, you'll get a short screen that might give you a message from the manufacturer. Then in the background you'll just see black and the Windows logo come through, and it will say 'Starting Windows.' What's going on there is that as soon as you hit the power button, your ROM is kicking in and starting up all those instructions for systems checks.
The part attached to the motherboard you're most likely to recognize is the hard drive.
The hard drive doesn't sit directly on the motherboard, but it is connected to the circuitry by electrical wire. The hard drive stores software you've put in there like Firefox, Word Pad or a music player. It also stores the data files those programs have created and used. Hard drive storage commonly begins at one terabyte now and goes up to two and a half terabytes.
Video and Sound Cards
Lets learn about the video card, or the graphics card. This card is used to process images so you can see them on your computer. As a standard computer user, the video card included with the system you are looking at will suffice. If you are a gamer, or really into working with photos or digital art, you may be looking for higher-end cards. These cards are more expensive, but typically have their own CPU for better and faster processing of images. Many video cards now allow for more than one monitor to be hooked up to the system.
