A reboot can be triggered via the start menu, but also via the key combination Ctrl-Alt-Delete. Reboots are distinguished between a hard reboot and a soft reboot. In a hard reboot, also called a cold reboot, the power supply is completely switched off once and then switched on again. In a soft reboot, also called a warm reboot, the system is restarted without interrupting the power supply. A reboot is often necessary after software installations, in case of a crash or if the system hangs.