If we talk about computer you imagine a screen with windows. 

We all are know only few parts of computer like keyboard,mouse,monitor etc but we don't know about the parts that actually runs the computer they parts are in cpu and they are 

Processor- it is part of computer that process computer and it also helps in operate the computer. Also it is the most important thing in computer without this computer can not operate  If a CPU can process two sets of instructions at a time it is called a dual-core processor; four sets would be considered a quad-core processor. The more cores, the more instructions at a time a computer can handle.

Ram - ram is a type of memory that helps computer to read information and store data for some time Usually more than one bit of storage is accessed by the same address, and RAM devices often have multiple data lines and are said to be "8-bit" or "16-bit", etc. devices.

Storage - in this we store data and also our important data that can use us at any time we want .Memory span varies; it is lower for multisyllabic words than for shorter words. In general, the memory span for verbal contents i

Graphic card- it helps to improve graphic of of the computer. It is basically uses in playing games it is not mendatory to run computer 

Motherboard- it is thing in which we attache all the things like processor,ram, storage, graphic card,etc 

Power supply- it is a thing that supply power to computer and computer basically run .

Computer is very important thing in this time but i see at amazon that computer sells at very high price but its specs are to low and they sell it at very high price but their worth is not at that level so this not good to buy computer at any online website. I basically prefer to buy it offline or buy computer parts and assembled it on home by help of this u can make a high end machine at very low price. You can buy some parts as new and some parts at old market by this you can down your price of making computer 

Computer software are also important for run computer the main software is window basically it is os that run computer there are many os in marjet but window is most popular os in this time a computer application that superficially resembles a word processor—but emphasizes the visual layout of the document's components