Ubuntu Wireless Driver reinstall

In the console, use this command

sudo ifconfig wlan0

Does it show your wireless card? If so, try connecting to a wireless access point like this,

sudo iwconfig wlan0 essid "Wifi SSID here"

If there's no problem, this command won't have any output. That being the case, finally close with this,

sudo dhclient wlan0

If all goes well, you'll at the very least be connected and know that the wireless itself works, and it's a matter of the connection using the GUI. But we'll have to see whether any of that works for you.

In the end, I used (I can't remember if sudo was required or not.)

(sudo) modprobe wl

to force the kernel to load the old driver, since it was there all along. Then, as stated above, the "missing" driver was reinstalled over the network. Weird.