To get back your wifi, type in a terminal:
root# rfkill list
and then you will see something like this:
0: phy0: Wireless LAN
Soft blocked: yes
Hard blocked: yes
1: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
As you can see the phy0 is soft and hard blocked, so you need to unblock it:
root# rfkill unblock 0
or
root# rkill unblock all
and then press “Fn + F2” for a Dell laptop, and then restart your networking:
root# service network-manager restart