The Blue Screen of Death (BSoD), also known as Blue Screen error, is a critical error screen displayed by the Microsoft Windows and ReactOS operating systems in the event of a fatal system error. It indicates a system crash, in which the operating system has reached a critical condition where it can no longer operate safely. Possible issues include hardware failure, an issue with or without a device driver, or unexpected termination of a crucial process or thread. The Blue Screen of Death is a full system failure at the Windows kernel level due to an issue with Windows drivers and/or hardware.

The term "blue screen of death" comes from the fact that a blue screen with white text appears describing the error when it occurs. The Blue Screen of Death can be caused by both hardware and software issues, such as faulty memory, overheating, malware, or software thats not playing well with other programs.

To troubleshoot a Blue Screen error, users should write down the error code and reboot their computer. Windows will attempt to determine the problem and fix it. In many instances, thats enough to address the problem. Users can also try getting the latest updates with Windows Update, help from other sources, or restoring Windows to an earlier point in time. If none of those steps help to resolve the Blue Screen error, users can try the Blue Screen Troubleshooter in the Get Help app.