There are many reasons why computers shut down themselves, including software or hardware errors. Some shutdowns are initiated as part of an update process, while many modern computers also shut down on their own to save power.
Diagnosing the reason a computer shuts down by itself is frequently difficult if the shutdowns are related to any number of possible hardware or software errors. Defective memory chips, inadequate or unreliable electrical power, software bugs, and malicious viruses are all potential causes of unexpected shutdowns. It is important to note any errors or odd behavior that occurred before the shutdown to efficiently troubleshoot the issue.
In cases where a software error is suspected, such as when the problem occurs shortly after the installation of a new program, uninstalling or updating the program is often a good first step. It is also possible to perform a system restore with many modern operating systems to return the computer to a functioning state. An example of this kind of procedure is the Windows Restore process used in Microsoft's Windows 7 and Windows 8 operating system.
Hardware errors are occasionally the cause of spontaneous computer shutdowns if the computer in question has begun to shut down itself after the installation of a new component. Removing the hardware is likely the best way to remedy the issue. In some cases, updating the driver software for the hardware resolves the shutdown issue.