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  1. Before switching on a computer, make sure that all the components are properly connected, and that the computer is connected to an active power source.
  • Turn on the switch at the source of the power supply.  If your computer is connected to a constant voltage Stabilizer or an Uninterrupted power supply (UPS), turn it on after switching the main supply. 
  • Turn on the switches on the System unit and the Monitor.  Switch on the power button on the Monitor first, then followed by that of the System unit.

After the power is on, the computer automatically goes through a process called Booting.  Booting is a term used to describe the starting up of a computer.  It is the entire process that makes the computer ready for use.

Types of Booting.

There are 2 types of booting, namely;

  1. Cold booting.
  2. Warm booting.

Cold booting.

This happens when a computer that was originally off is switched on by pressing the power button on the system unit.

Warm booting.

This happens when a computer that was originally on is forced to restart by pressing the Restart button on the System unit or by pressing a combination of keys on the keyboard (Ctrl+Alt+Del).

In Windows operating systems, one can use the Restart option on the Shutdown dialog box to perform a warm boot.

When Power is switched on, the computer starts by checking all its components to determine whether they are available for use and whether they are functioning correctly.  It does this by executing a small program called the Power-On-Self-Test (POST) that is permanently stored in ROM.

POST prepares the computer for use by instructing it to perform a number of diagnostic tests when booting up.  It instructs the computer to check the memory (RAM) to make sure it is operating correctly; check the CMOS (BIOS), Hard disk controller, Floppy disk drive controller & the Keyboard

During this process, some monitors display information showing the status of each device being tested.  If a problem is found, e.g., in case one of the devices is faulty or missing, the process will halt and display an appropriate error message on the screen indicating to the user where the problem is located.  Sometimes, an error code is displayed with the message, or an abnormal number of beeps are sounded.

The special program that directs the POST process is called the Basic Input Output System (BIOS).

Shutting down a computer.

After finishing working with the computer, the user must follow the correct procedure of shutting down the computer in order to ensure that loss of data, damage of programs and computer components does not occur.

  1. Save all the work done on the computer, and close all programs that may be currently running.
  2. Remove any floppy disk you might have inserted in the computer.
  3. Follow the proper shut-down procedure required before switching off the computer.

For example;

To turn off any computer running Windows operating systems:

  1. Click the Start button on the screen, then select Shut Down from the list.
    1. In the prompt that appears, select Shut down, then press the Enter key on the keyboard.
    1. After a few seconds, the message “It is now safe to turn off the computer” appears on the screen.  Switch off the System unit, then the Monitor.

Note.  Some system units switch themselves off automatically.  In such a case, press the button on the Monitor to turn off the screen.

  • Press the button on the monitor to turn off the screen.
  • Switch off your Printer and any other output devices.

Review Questions.

  1. (a). What is meant by the term ‘booting up’?

(b). Differentiate between cold booting and warm booting.

  • Write down the procedure to be followed when switching on a computer.
  • Complete the abbreviation ‘POST’ in computer technology and explain briefly its purpose.
  • List down the steps that must be followed before switching off the computer.


The Keyboard is a computer input device by which data & instructions is typed into the computer memory.

It enables the user to enter data & instructions into the computer by pressing its keys.

Types of Keyboard.

  1. Standard Keyboard – has 99 keys.
  2. Enhanced Keyboard – has between 102 & 105 keys.


The Keyboard of a computer consists of keys similar to those of a typewriter.  It contains the usual range of alphabetic characters (A – Z), digits 0 – 9, and other symbols frequently used to represent data items.  However, it has some command keys for giving special instructions to the computer.


Data & programs are input into the computer by pressing the appropriate keys.  When you type data into the Keyboard devices, it converts it into machine-sensible forms.


Most Keyboards have a total of 101 keys, which are divided into 5 different groups: –

Function/ Command keys.

These are the keys located along the top of the Keyboard marked F1 up to F12.  They are used to issue commands into the computer.

Each of these keys is used to perform a special function in various application packages, e.g., F1 is used in most applications for help.

Function keys are used differently by different applications, i.e. their functions vary with different programs, and are therefore sometimes called Programmable Keys.

Alphanumeric keys.

This section consists of alphabetic & numeric keys.  Alphanumeric keys are mostly used for typing of text.

It has the 26 letters of the English alphabet marked on them in capital letters, and Number keys arranged in their natural order from 0 – 9.  Along with these keys are Punctuation marks (comma, full-stop, etc) and some Symbols. 

At the bottom of the alphanumeric keys, is the Space bar, which is used to separate words or sentences from each other (or to create a blank space after typing each word).

Numeric Keypad keys.

It is on the rightmost part of the Keyboard.  It has keys with digits (numbers) 0 – 9 marked on them in rows from the bottom upwards.

The keypad also has some mathematical symbols marked on its keys.  They include: the multiplication sign (*), subtraction sign (-), addition sign (+), division sign (/) & the decimal point (.).

The Keypad is used for fast entry of numeric data into the computer.

Note.  The numbers on the Numeric keypad can only be used when the Num Lock key is turned on.

Directional (or Cursor positioning) keys.

They are used to move the Cursor (insertion point) within the window of an application.

They include; Page Up, Page Down, Home, End, & the four Arrow Keys

Arrow keys:

To move the cursor one character to the right in a Word processing document, press the Right arrow key; to move the cursor one character to the left, press the Left arrow key.

To move the cursor one line up, press the Up arrow key; to move the cursor one line down, press the Down arrow key.

Page Up & Page Down:

To move the cursor up one page in case the document has many pages, press the Page Up key; to move the cursor down one page, press the Page Down key.

Home & End keys:

To move the cursor to the beginning of the current line, press the Home key; to move the cursor to the end of the current line, press the End key.

Editing keys.

They are used to delete or insert characters in a document.  These are:

Backspace key.

It has a backward arrow (¥) marked on it.

  • Used to erase characters to the left of the cursor (i.e., from right to left on the same line). 

When pressed, it makes the cursor move one space backwards and the immediate letter or number to the left is erased.

Delete (Del) key.

It is used to erase characters to the right of the cursor, (i.e., from left to right).

Insert (Ins) key.

  • Used in a word processor to switch between the Insert mode & Overtype mode.  When pressed, it helps the user to insert text in the middle of a sentence or replace a character at the cursor position (i.e., overwrite the text).

Special PC operation keys.

They are used in combination with the other keys or on their own to perform special functions/tasks, or to give special instructions to the computer.

Examples; Esc, Tab, Caps Lock, Shift, Ctrl, Alt, Enter, Num Lock, Scroll Lock.

TAB key (                                 ).

It is used in certain programs such as Word processors to move the text cursor or a certain text at set intervals on the same line to the required position on the screen, e.g., 10mm, 20mm, etc.

A Cursor is a blinking underscore ( __ ) or a vertical beam (I ) that shows where the next character to be typed will appear.

CAPS Lock.

Used to switch between capital (uppercase) letters & small (lowercase) letters.

When pressed on, an indicator with a Green light appears on the top-right hand corner of the Keyboard, and all the text typed will appear in capital letters.  When pressed off, all the text typed will appear in small letters.

SHIFT key (      ).

This special key works in combination with other keys.

  • It can be used to get single capital letters.  Hold down the SHIFT key & press an alphabet key to get the letter in its capital form.
  • It is used to get the punctuation marks on top of the Number keys or the symbols on top of certain keys especially on the alphanumeric section.

To get the punctuation mark on top of a number key or the symbol on top of a certain key; press & hold down the SHIFT key before pressing the required key.

ENTER key ().

  • It is used as a RETURN key.  When pressed at the end of a text line or paragraph in a word processor, it forces the text cursor to move to the start/ beginning of the next line or paragraph.
  • It is used to issue completion commands to the computer.  It is used to instruct the computer to carry out (execute) a command that has been typed or selected on the screen.


It generates special code for the computer.  In some programs, it is used when you want to quit doing some task, i.e. escape from or to cancel a task.


It controls various functions in combination with other keys, e.g. CTRL+”S” is used to give the command for saving the text/object.

Commonly confusing keys.

Some key shapes cause much confusion.  If you use the wrong key, the process you are working on may not work as expected, but it may be very difficult to determine what is wrong.

The I, 1, l and o, O, 0 keys.

Look closely to spot the difference between capital “I”, one (1) and “l” (lowercase “L”), and between small “o”, capital “O” and zero “0”.

The Slash (/) and Backslash (\) keys.

The slash (“/”) is used as:

  • A division symbol when writing a formula.
    • A command key to get into the menus in Lotus 1-2-3.
    • To separate parts of a path in a UNIX file name.

The backslash (“\”) is used:

  • In Lotus 1-2-3 to fill a cell with a character.
    • In MS-DOS to separate parts of a path in a file name.

The Space, Hyphen () and Underscore ( _ ) Keys.

The Space is entered using the Spacebar on the keyboard.

Note.  A blank space is a printing character; it takes up memory, has an ASCII code, and is printed on the screen in the same manner as any other character.

The Hyphen key (dash or minus) & the Underscore (underline) are on the same physical key top.  To get the underscore, use the SHIFT.

The Underscore is often used in places where a space is needed to separate individual words, but is not legal in the context.  E.g., the filename TAX 1990 is illegal in MS-DOS because of the blank space between TAX and 1990, but TAX_1990 is legal.  The Underscore takes the places of the blank space.

Single & Double quote, Accent grave, and Tilde.

Single quote () & Double quote ().

Both symbols are on the same physical key top.  To get the double quote, use the SHIFT.

Accent grave (`) & Tilde (~) are found on the same key top. The Tilde is used in Mathematics, foreign languages, or in UNIX operating system to indicate the home subdirectory.

The Parenthesis (  ), Square brackets [ ], & Curly braces {  }

Each of these symbols is used differently depending on what program you are running.

Mathematical  symbols (+,, *, /, ^).

Slash (/)                                         – used for division,

Asterisk (*)                                    – for multiplication,

Plus (+) symbol                             – for addition,

Minus () symbol                           – is used for subtraction,

Up carat (^)                                  – indicates exponential (raising to a power).

Practical Keyboard skills.

When using the keyboard, observe the following typing rules:

  1. Sit upright with both feet firmly on the ground, maintaining an alert posture.
  2. Place the material to be typed on your left in a position you can read without strain.
  3. Rest both hands on the keyboard with fingers resting on the Home keys.

Home keys are the keys on which fingers rest during typing in readiness to press other keys.  The home keys for the left hand starting with the small finger are A, S, D, F with the thumb on the Spacebar, while those of the right hand are the apostrophe (‘), semicolon (;), L, K with the thumb on the Spacebar.

  • Start typing the text slowly at first, making sure you are using all the ten fingers, and that you press the key nearest to the home keys with the closest finger, e.g., to press Q, use the small finger on the left hand, while to press J, use the index finger on the right hand.

Descriptive Questions.

  1. Define a Keyboard.
  2. (a)            Give the TWO types of Keyboards found in the current market.

(b)  State and briefly explain the functions of five categories of keys found on a standard keyboard.

  • State the use of each the following section or combination of keys on the keyboard:
  • Function keys.
  • Numeric keypad.
  • Arrow keys.
  • Control key.
  • Name 3 main sections of the Keyboard that are used in typing.
  • What is the difference between Function keys and Special PC operation keys?
  • State the functions of the following keys on the keyboard.
  • Caps Lock.
  • Spacebar.
  • Shift Key.
  • Enter Key.
  • Backspace.
  • Delete.
  • Escape.
  • Num Lock.
  • Give two uses of the SHIFT key.


A Mouse is a pointing device that enables the user to issue instructions to the computer by controlling a special mouse pointer displayed on the screen.

A Mouse consists of 4 parts: –

  1. A Casing – to assist in holding the mouse in the hand.
  • A Roller ball – used to slide/move the mouse on a flat surface.  It also enables the cursor to move on the screen as required.
  • The Sensor Buttons (Right & Left) – used for making selections.
  • A Cable – connects the mouse to the System unit.

Using the Mouse.

To use a mouse, hold it in your hand and move it across a flat surface or on top of a table.  When you move the mouse, an arrow-shaped pointer called the Mouse pointer moves across the computer screen in the same direction.  The pointer is usually controlled by moving the mouse.

To select an option/ item on the screen;

  • Position the tip of the pointer (cursor) over the item to be selected;
  • Press a button on the mouse to make your selection.

When using the mouse, observe the following rules:

  1. Place the mouse on a flat smooth surface.
  2. Gently hold the mouse with your right hand, using the thumb and the two rightmost fingers.
  3. The index finger should rest on the left button, while the middle finger rests on the right button.

Terminologies associated with the use of a Mouse.

Point: – this means moving the mouse until the tip of the pointer on the screen is over the item you want to select.

To select an item on the screen, point the item, then press a mouse button.  Use the Left button (Primary button) for most tasks or the Right button (Secondary button) to quickly accomplish common tasks.

Clicking: – pressing & releasing the left mouse button once.  A click usually selects an object/item on the screen.

Double-clicking: – pressing the left button twice in a row (in a quick succession) without moving the mouse.  Double-clicking usually opens a file or starts a program.

Right-clicking: – pressing the right mouse button once (or, selecting an item by use of the right mouse button). 

A right click usually displays a list of commands from which the user can make a selection.  This list of commands is called a Shortcut menu or Context-sensitive menu.  This is because; the commands on this menu apply to the specific item that has been right-clicked.

Shortcut menu:

  • A list of commands that appears when you right-click an object.
  • A menu that shows a list of commands specific to a particular right-clicked item.

Drag and drop: This is whereby the user moves an item from one location on the screen to another.

To move an item on the screen by dragging;

  1. Point to the item you want to drag.
  2. Press & hold down the left mouse button.
  3. Slide the mouse until the pointer reaches the desired position on the screen while still holding down the mouse button.
  4. Release the mouse button to ‘drop’ the item in its new location.

Review Questions.

  1. What makes a mouse move a pointer on the screen?
  2. State THREE advantages of using a Mouse instead of a keyboard.
  3. Explain the meaning of the following terms associated with the use of a mouse:
  4. Mouse pointer.
  5. Clicking.
  6. Double-clicking.
  7. Right-clicking.
  8. Drag and drop.
  9. Distinguish between:
  10. Click and right-click.
  11. Double-clicking and dragging.
  12. What is a Shortcut menu?
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