Today everyone are use a personal computer in everydaylife .And incressing number of user are make a PC more cheaper and easier to use in everyday but even it cheaper a PC are classified into many type depend on user .PC can be divided into two big group ,first a Desktop and a Laptop .They are classified by their size .it have a same PC system consist of PC software and PC hardware .PC hardware are Mechanical and elctronic equiment include CPU ,Main memory and Peripheral .There are two type of main memory they are RAM and ROM .Peripheral are physical units attached to the computer include input device ,output devices and storage devices .