An inviolable rule of modern computers: Never trust the shutdown command to actually shut down the computer.

1) Issue shutdown command.

2) Wait a reasonable amount of time. Lights should flash and go out. If they do not go out in a reasonable amount of time or the OS wants to install updates or otherwise does not gracefully comply with the shutdown order, proceed to next step.

3) Disconnect all power sources: Unplug, remove batteries, cleave with axe, etc., until no power can be drawn by the system.

4) Confirm system is no longer powered and stow for transport.

Under no circumstances skip step 4. Often modern computers have been sabotaged to ignore shutdown commands and will consume power in direct contravention of administrative directive. This is a fault condition which should immediately be rectified with step 3. Be prepared to open the computer enclosure and physically separate power leads or sources from processing elements. This may require the use of prying, cutting, grinding, or impact tools. Ideally this should not be necessary however certain vendors and petty bureaucrats may attempt to interfere with the shutdown procedure. This should be considered a hostile act; no countervailing response should be considered too extreme in pursuit of prompt system shutdown.