A computer is an electronic device that receive data, processes data, stores data, and produces a result.
Hardware is the physical parts of a computer
Software is a set of instructions that tells the computer what to do
There are lots of different computers here are some. Desktop Computer - designed to be used on desktop, Notebook/Tablet computer - designed to be used on a desktop but still small enough to be portable, and a Laptop Computer - designed to be small enough and light enough to be used on your lap.
There is lots of hardware. Modem - connects your computer to the Internet, CPU - Central Processing Unit is the brain of your computer, SMARTBoard - Interactive whiteboard thats connected to a computer and a data projector.
There are two different types of software, Systems Software - controls the operation of the whole computer system, and Application Software - performs a specific task. Examples of software are MS Word, MS Excel, MC Access, etc...