Possible Duplicate:
Wireless doesn’t work on a Broadcom BCM4312
I installed Ubuntu 12.10 amd64 on a macbook 3,1. Wireless was working until I ran a "software update", and now I am without wireless.
I have an internal Broadcom Network Adaptor (BCM4321).
Your problem looks similar to mine, and I think the new kernel and broadcom drivers are the connection. I ran
sudo apt-get install linux-headers-generic
sudo apt-get install --reinstall bcmwl-kernel-source
sudo modprobe wl
which I found here - Wireless does not work anymore after software update with Ubuntu 12.10 on a Dell Latitude E6230
and it worked for me on my Acer Laptop.
