To ensure that a device's power is always on, enable Power-On in the BIOS.
Connect a keyboard to the device.
After connecting the power cord to the device, hit the ESC key quickly and repeatedly until the following screen appears. At the top, select the Advanced tab.
Select Power Management Configuration.
Hit SHIFT+'+', without the quotes, to change EuP Function to Disabled.
Hit SHIFT+'+' without the quotes, to change Power-On after Power-Fail to Power On.
Hit F4, then hit Yes, and the device will reboot.