In Windows NT, Windows 2000, and Windows XP, a blue screen of death occurs when the kernel, or a driver running in kernel mode, encounters an error from which it cannot recover. This is usually caused by a driver that throws an unhandled exception or performs an illegal operation. The only action the user can take in this situation is to restart the computer, which results in possible data loss due to Windows not properly shutting down.

A BSoD can also be caused by a critical bootloader error, where the system is unable to boot although it already knows that Windows exists on it. In such cases, there is no memory dump and little information is displayed on the screen. The problem can usually solved by booting from the Windows XP install CD.