If Network Manager claims that Wifi is disabled by a hardware key, take these steps:
- Check if hardware keys disable the wifi (duh!) - this may include key combinations such as Fn-F2.
- Check rfkill list if some devices are blocked and unblock them with sudo rfkill unblock all
- If you have one blocked device, this may block all other devices due to a bug in Network Manager. Hence removing the modules of all other devices may be necessary to enable a device which is actually already unblocked. (e.g. sudo rmmod rf2800pci and sudo rmmod ideapad_laptop).
Worked for me - let me know how this works for you.