The "Blue Screen of Death" (BSOD) is an error screen displayed by the Microsoft Windows operating system when it encounters a critical system error. This screen indicates that the system has crashed and cannot continue running safely. The BSOD typically includes error codes and messages that can help diagnose the underlying issue. When a BSOD occurs, the computer may automatically restart or require a manual reboot. Common causes include hardware failures, driver conflicts, or software issues. Users can often troubleshoot these problems by checking the error codes or using recovery tools provided by Microsoft.