Motherboard:

This is the central circuit board of a computer. It is sometimes called motherboard, mainboard, logic board etc. The commonest form factors in use in PCs are: AT, BTX but the ATX brought about many chances on a PC. The mainboard contains connectors for power supply unit, peripheral devices, additional boards (sound, graphic, NIC… cards). It also houses the CPU, memory, mass storage interfaces and the chipset. All these communicate with each other via the various buses.

It accommodates every other thing in a PC.

Motherboard

Processor:

The Central Processing Unit (CPU), popularly known as Processor is the main computer device that has almost all processing powers of any personal computer (PC). In PCs, the single CPU located on a chip is simply called Microprocessor. It is here that most calculations take place.

The arithmetic logic unit (ALU), which performs arithmetic and logical operations and the control unit (CU), which extracts instructions from memory and decodes and executes them, (calling on the ALU when necessary) are the commonest components of a CPU.

The Random Access Memory (RAM), input/out (I/O) devices are very essential for any CPU to perform. The CPU is located in a socket on a motherboard. It is common today that two (dual-core) or more (multi- core) similar CPUs reside in same die accessing the system-bus (FSB) differently. PCs with such features are multitasking.

Intel and AMD among others, are the leading CPU producers. In late 2008, Intel brought Intel i7 processors into the PC world. Equipped With the Quick Patch Interconnect (QPI) and other technologies, i7 processors are fast. This could be icompared to the AMD standard HyperTransport (HT) technology that has been in use since its K8 architecture.

CPU

Random Access Memory (RAM):

It is most commonly found on a computer, and other devices such as a printer or a graphic card. Since RAM is faster to write to and read from, than hard disk, CD/DVD and floppy disk, it is where in a computer, the operating system, application programs, and data currently in use are kept for a quick reach by the CPU. There are different types of RAM.

RAM

Graphic card:

The graphic card is a very essential component of a personal computer  (PC).  It is  an expansion card (PCIe and AGP) located on motherboard that processes and outputs the images seen on the monitor. In other words, without the graphic card, the PC user cannot communicate with the PC. Very import components among others of  the graphic card are the graphic processor - GPU- (2D and 3D types), Random Access Memory Digital-to-Analog Converter (RAMDAC) for display output, amount of RAM etc. The processing powers of the graphic processor determines how much relieve the microprocessor can receive here. Some PCs have integrated graphic cards in the chip found on the motherboard.

Graphic Card

Hard disk drive HDD:

The computer hard disk (or hard disk drive) is the main non volatile data storage center of your system. It is here that all the programs and data are stored between the periods the computer being used and when it is short dawn. Of all other permanent data storage types in a PC, like CD/DVD-ROMs, Tapes, External hard drives, the Internal hard disks are the most important. The size and speed at which they work vary.
The rotational speed of a hard disk varies from 4500 to 7200 rpm. Disk access time is measured in nanoseconds. A lot of progress has been made today in terms of speed and capacity of hard disks. top

Hard Disk Drive

Mouse:

This is an input device attached to the PC either via the Serial/PS2 or USB ports located on the motherboard. It is one of the most known devices to the PC users. The PC mouse was made popular by Apple computer in that it made it a standard for its computers. Today, there are varieties of mice out there: wireless, optical, wheel mice etc.

The mouse has among other features two buttons on top: left and right buttons that users click on when the point at the command they have selected. On a click on such selected command, the users get feedbacks.

It is an input device

Mouse

Keyboard:

It is an input device

Keyboard

Monitor:

The monitor or display as often referred to enables the computer user to communicate with the computer using the mouse and the keyboard. The monitor is connected to the video card (graphic card) using the digital or the analog interface at the back of the computer. The older type of monitor, Cathode Rays Tube (CRT), has been replaced by the Liquid Crystal Display (LCD) monitor. This technology is used in Laptop, and flat panel monitor. It uses less energy and space when compared to CRT monitor. The TFT (Thin Film Transistor) brand of the flat LCD monitor is of a very high-quality. The monitor clean.

Monitor magnets dirt and dust very fast, because of electrical charge it generates. First, turn off the monitor and disconnect it from power source. Use a clean, soft cloth sprayed with glass cleaner, in wiping the screen of the monitor. Do not press too hard when cleaning an LCD. Do not attempt cleaning inside of the CTR monitor if not trained for that because it still remains a good quantity of voltage even when power has been turned off. top

It is an output device

Monitor

Power Supply:

The power supply supplies electricity to the personal computer. It converts the alternative Current (AC) from the wall outlet into Direct Current (DC). It supplies the PC components with DC as maybe required. The power supply form-factor commonly in use in  PCs today is the ATX. If it is damaged, the PC will never boot again. Or when degraded, the PC components will not receive enough power. Standard power supply converts the incoming 110V or 220V AC into various DC voltages suitable for powering the several computer's components. A low quality power supply can cause instability and may greatly reduce the life span of a good system unit. A standard has been set since ATX12V was developed. It Uses a 24-pin Main Power Connector over 20-pin Connector. The power supply should not be neglected.

Standard power supply would typically be able to deliver around 350 Watts. The more components a PC has, the greater the power required from the power supply. A power supply with more watts, than required by the total components (such as Processor, Graphic and sound cards, etc) in a PC, is expected to perform better and will increase productivity. Dust accumulation in the device may cause a breakdown. Ensure that the fan(s) are working properly.

Power Supply

CMOS Battery:

The CMOS battery is located on the motherboard. When a PC is turned off, the CMOS battery enables it retain the system time and settings.

CMOS stands for Complementary Metal-Oxide Semiconductor. This is a semiconductor chip located on the motherboard. The CMOS battery supplies power to the semiconductor chip. In other to retain the very important information stored in the CMOS chip such as the system time (Real Time Clock - RTC) and system settings for your computer, the battery is required. The information may be lost if the PC is turned off for a long period or if the battery is discharged. When this happens, such errors as: CMOS Read Error, CMOS Battery Failure, or CMOS checksum error will be received when the PC is started. Before replacing the battery, write down the system settings, if not yet lost, since only the default system settings will be loaded once a battery is replaced.

To fix this error, the CMOS battery has to be changed or the let the PC run for about 24 hours in other to recharge the battery. If the errors persist after the battery replacement, then the error is fatal. This may indicate that the motherboard or the power supply is bad. top

CMOS Battery