Software is the combination of Instructions and Data, known as machine code that forms the building blocks of applications such as Word Processor, Computer Game or Spreadsheet. This machine code lives in the memory of the computer as billions of little on off switches.   Software is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it. In other words, software is a conceptual entity which is a set of computer programs, procedures, and associated documentation concerned with the operation of a data processing system. We can also say software refers to one or more computer programs and data held in the storage of the computer for some purposes. In other words software is a set of programs, procedures, algorithms and its documentation.

In the present day world, computers play a significant part in our daily life. To provide us different services, different types of software are run on these computers. Computer software is generally of three types: System software, Application software and Off-the-shelf Software.  System software, this is the software which is actually running your computer while Application software is developed to handle a specific task and are developed to cater for the specific requirement of the user.  Off-the-shelf software generally provides some standard functions and they do not cost much.  Now days, another kind of software are available. They are called Open source software. This type of software generally does not cost you anything and allows you to make copies and pass on to others. Sometimes, the source code of the software is also provided which you could modify as per your requirement. Computer software developed from the theories and formulas of computer and this job was initiated by the expert mathematicians. With the software technology reaching its peak, there are rapid advancements in the computer technology in the recent times.

Remember, software is to a computer as music is to a CD player, or as a movie is to a VCR. There are thousands of programs available for your PC, and no two people have exactly the same programs on their computers. The programs that are installed on your computer can all be found, and started from, the All Programs menu (or some program group that's accessible from All Programs menu).