I lost wireless on the last Ubuntu upgrade. I searched the forums but for a while it had me stumped. As I have dual-boot I went into the XP side and the wireless worked there fine. But not back in Ubuntu.
In the terminal, if I ran ‘iwconfig’ I got:
lo no wireless extensions.
eth0 no wireless extensions.
Eventually I got help from here.
I downloaded a new wireless driver from the link there. I saved it to my desktop and then pasted the following in a terminal:
tar -jxf /home/graham[or your user name]/Desktop/compat-wireless*.bz2
sudo make install
sudo make unload
sudo make load
Text scrolled by for ages, I pressed ‘enter’ a few times, and then my wireless sprang into life. Whew!
If it happens to you, this is the answer, but I hope you are spared.