First of all I'm new to Ubuntu, just bought a laptop with Ubuntu yesterday.

I disable wireless networking in the upper right corner, and I don't have option to enable it back.

I tried a lot of things and none is seems to work:

1. I installed Wicd network manger, and it says no wireless network found, but i assure you there are several of them as my smart tv can detect them.

2. when I type rfkill list, I get this:

   0: dell-wifi: Wireless LAN
       Soft blocked: no
       Hard blocked: no
   

3. when I type ifconfig wlan0, I get this:

   wlan0: error fetching interface information: Device not found