5. Operating Systems
Most computers are purchased with an operating system (OS) already installed to make it easy for you to get started using your computer. The operating system is a set of software (a program) that enables the computer to function by controlling the hardware device, allowing network capability and allowing other software applications to work with the hardware.
There are many operating systems available but the most common systems are Microsoft Windows®, OS X (Apple)®, Android® and Linux. The operating systems are frequently updated with new versions made available every few years. You don't always have to upgrade to a new version but over time, the old systems become difficult to use and are no longer supported by the company that creates the operating system.
It is important to know which version of the operating system is installed on your computer in case you need to troubleshoot problems running certain software applications. The logo of the operating system is the quick way to determine the OS.
(This is the Windows® logo 
)
To confirm the version number of the operating system (in other words, how old it is), you usually have to go into the settings folder of your device. Most companies who make operating systems provide detailed instructions online and/or an auto-detect feature to locate the version.