The realities of today are such that to successfully work on a computer, and especially on the Internet, it is not enough just to have the appropriate skills. To an important extent, the results of the work depend on how well the user knows how to protect his computer and the information stored in it. Data protection issues are of particular importance in light of the fact that modern fraudsters are constantly improving their “skills”, and a loss of vigilance can lead to very sad consequences. The book examines in detail various types of emergency situations that can arise when working on a computer, and analyzes the reasons for them occurrences and provides advice and recommendations for solving these problems. The book pays special attention to the dangers that await a computer user when working on the Internet, as well as issues of restoring the operating system and data. Studying this book will allow readers to quickly master the skills of saving and protecting information from errors, failures and intruders.