Quantum computers are from the past. Software is not stored anymore on physical devices but is always flowing through the network it resides. Even if this network is only one device, who’s actually extremely rare / see Fancy Wearable Computers /.
Powering off a computer is something inconceivable. It’s like killing a person. The fact that the software has no hard-copies and is constantly flowing makes it ever evolving. If it's an AI, it's constantly learning and adapting, if not, it's just increasing its data collection.