CPU - Central Processing Unit
a microchip that is installed on a motherboard and acts as the computer’s brain - performing calculations and coordinating the hardware components.
Hard Drive
a magnetic storage device for digital data
RAM
Random access memory (or simply RAM) is the memory in a computer that is used to store computer programs while they are running any information the programs need to do their job.
Optical Drive
'Optical' means light. So an 'optical device' makes use of light in order to work.
Graphics Card
This is a device which fits into an expansion slot on the Motherboard and can be used to produce high quality displays for your monitor.
Monitor
A monitor is an output device similar to a television screen. It receives signals from the computer and displays that information for the user to view.
Mother board
The Motherboard is the main printed circuit board in the computer.
It has many sockets into which the CPU, memory (RAM and ROM), cards (sound, graphics, network interface etc) and peripheral devices are connected.
Software
All computers need a set of instructions to follow in order to run or even boot up.
These instructions are called "software code" or just "software" for short.
Applications
An application in a software program which enables you to perform a range of useful tasks. Examples of applications are word processing programs, spreadsheet software, databases or graphics packages
Virus
A computer virus is a piece of program code that, like a biological virus, makes copies of itself by attaching itself to another program.