The modern world can no longer be imagined without a computer, laptop or mobile phone. However, all these devices are just a bunch of hardware without software. For a computer there are several operating systems. Most modern Estonian users prefer Microsoft Windows. Windows has an extensive series of Windows products. The most popular and well-known of them: Windows XP, Windows 7, Windows 8, Windows 10. Successful and correct installation of Windows is no less important than choosing a good modern computer.