It might be the case that earlier wireless was working and then it stopped working
Follow the simple steps here....
1. Restart networking
Follow the simple steps here....
sudo /etc/init.d/networking restart2. Disable the "Support for Atheros 802.11 wireless LAN cards" on system/administration/Hardware Drivers, and reboot your box.
3. Restart
sudo reboot
That's it, Cheers! Still having problem follow the instructions here
