Starting the computer when its power is turned off. To perform a cold boot if the computer is running, select Shut Down. Once the machine is off, turning it back on performs the cold boot.
If the computer locks up, a cold boot is necessary because a restart ("warm boot") may not be sufficient. A cold boot removes power and clears memory (RAM) of all internal data and counters that keep track of operations, which are created by the OS and applications when they run. Erratic program behavior is often cured with a cold boot, also known as a "hard boot."
Remove the Power
Even when shut down, computers may occasionally retain settings in RAM. The only way to absolutely guarantee RAM is cleared is to remove the power source, which means unplugging a desktop computer or removing the battery in a laptop. Laptops with non-removable batteries are typically cold booted (reset) by holding down the power button for 10 or more seconds. Sometimes another key or button must be pressed along with the power button.
A/V Equipment
TVs, A/V receivers, cable TV boxes and streaming media hubs generally draw power when turned off, and many devices have no on/off switch. They must be cold booted by unplugging them from the wall outlet. Contrast with
warm boot. See
boot,
clean boot and
hard reset.