Fix 'Wireless is disabled by hardware switch' on Dell-Laptop

The cause:

One possible cause of this is if you have a network adapter that is used for both WiFi and Bluetooth, turning off the Bluetooth may disable the WiFi at the same time leaving you unable to connect to WiFi.

The solution:

First run these two commands in the terminal (Ctrl+Alt+t):

rfkill unblock all
rfkill list

If the output of the last command is as below (with 'blocked no' for all adapters), the issue should be resolved.

3: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
20: dell-wifi: Wireless LAN
    Soft blocked: no
    Hard blocked: no
21: dell-bluetooth: Bluetooth
    Soft blocked: no
    Hard blocked: no
22: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no

If instead the output has 'blocked yes' for any adapters, move on to the next step.

Run the following command:

sudo rmmod dell_laptop

The output will be either blank or as below. If it is blank press the keyboard short-cut Fn+F2 and run it again as we want to see the following output.

ERROR: Module dell_laptop does not exist in /proc/modules

The following command should now unblock the network adapters.

sudo modprobe dell-laptop

To check the command worked you can run rfkill list again to see the following output with 'blocked: no' for all adapters.

3: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
20: dell-wifi: Wireless LAN
    Soft blocked: no
    Hard blocked: no
21: dell-bluetooth: Bluetooth
    Soft blocked: no
    Hard blocked: no
22: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no