This is very frustrating but the fix is usually easy once you read this blog. It's very frustrating when you find that your Linux / Ubuntu laptop's wifi will NEVER work unless it is plugged into the power. The wifi menu may say "Wifi disabled by hardware switch". You may find that your laptop has no switch or has a function wifi button on the keyboard but this does not work or have any effect.
The cause is usual a "wmi" kernel module and simply doing an........