A computer's software refers to a program (or a group of programs) which give a computer instructions on what to do and how to operate. Software programs can provide one main task, or multiple main tasks.

As an example, a program designed to edit digital photographs has one key task (i.e. to allow for editing of photos) – naturally it would have numerous sub-tasks though (i.e. red eye removal, color correction features, resizing and cropping/cutting of an image).

On the other hand, a computer's operating system (a complex piece of software which basically handles and runs the entire computer) would carry out many main tasks – for example handling input and output (i.e. the user typing in with a keyword, or audio coming out of speakers), memory allocation, managing the computer's hardware components (these are the electrical components which power a computer) and much more.

Software can be grouped into roughly two groups: application software and systems software. Essentially, software which facilitates just one main task (for example, photo editing software as in the above example) would be counted as application software. This is contrasted to systems software which refers to complex, multi-task programs which help to run the entire system – such as an operating system.

These two main groups of software are discussed in more detail below:

Application Software

This is software which is installed on an operating system (See "Systems Software" below for more information). As mentioned above, this type of software tends to perform just one main task. Another example of application software would be a website browser: this is the program which you are probably using right now to view this article. Examples of a browser include Internet Explorer, Google Chrome and Mozilla Firefox. In short, their main task/function is to facilitate you in surfing the internet.

Other types of application software are as follows:

Word Processing – this type of software allows you to type up documents and letters. Examples include Microsoft Office Word and Open Office.

Antivirus Software – this type of software helps protect your computer system against malicious threats such as viruses and malware. Examples include Norton Antivirus, Kaspersky Antivirus and AVG Anti-virus.

Photo Editing – this type of software can be used to edit and manipulate photos and other digital images in various ways. Examples include Paint.net, Corel PaintShop Pro and Adobe Photoshop.

Systems Software

This type of software is quite accurately described as being at the very core of any computer system. Without systems software, a computer could not really function.

In short, it manages every aspect of a computer system – from how the hardware interacts with the software ('drivers') to giving the user an interface and platform to interact with the system ('operating system'). The operating system – or 'OS' - is the software that loads up after your computer is switched on. It's where all application software is installed on. Examples of an OS include Microsoft Windows (XP, Vista, 7 etc), Linux (Ubuntu, CentOS) and Apple Mac OS X.

Other types of systems software include device drives (these make the hardware components function correctly with the software and computer system) and utilities (these are also called 'utility tools' and they help monitor, maintain, check and analyze different parts of a computer; such as 'Task Manager' and 'Disk Defragment on Windows OSes).