If it says "No wireless networks available", that proves that WiFi is already enabled.
The problem is simply that your laptop's WiFi isn't finding any networks for some unknown reason - - it's not because wireless is disabled.
Restarting your laptop and WiFi router should correct the problem, but bear in mind that it will take a while for your router to 'resync' and be ready to use after restarting it, so give it time to settle down before trying to connect your laptop to it.