I gather your wifi is not working, and that it just stopped working, but I don't have enough information to figure out what has changed to have this occur.
A good start, however is to run
Code:
rfkill list all
from a terminal. It will tell you if the there is a hardware or software switch keeping your wifi off.
Quote:
io@io:~$ rfkill list all
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
1: acer-wireless: Wireless LAN
Soft blocked: no
Hard blocked: no
If it is soft blocked, it will say 'yes' rather than 'no'
Code:
sudo rfkill unblock wifi
check again with
Code:
rfkill list all
If it is hard blocked 'yes', find and flip the switch, check again with
Code:
rfkill list all
