Double boot
Double boot (also known as cold double boot, double cold boot, double POST, power-on auto reboot, or fake boot) is a feature of the BIOS, and may occur after changes to the BIOS' settings or the system's configuration, or a power failure while the system was in one of certain sleep modes. Changing some parameters in the BIOS will cause this issue, even for items as simple as initializing the current CPU and memory clocks.