I was suffering from disabled Wifi drivers after updating via automatic updates.

Version Ubuntu 8.04LTS
Machine: Acer Extensa 5220

SOLUTION:

Moved previously downloaded madwif drivers from 'madwifi-hal-0.10.5.6-r3816-20080724' to a new folder with a shorter name called 'madwifi' This stopped a problem with 'make' which said "No rule to make target error STOP" caused I believe by the long foldername (?)

Then I followed instructions at the main Acer Aspire One "how-to"(https//help.ubuntu.com/community/AspireOne110L#WLan) EXCEPT it only worked when I issued every command preceded by 'sudo' See below:

Code:
sudo make clean
then..

Code:
sudo make
sudo make install
then

Code:
sudo modprobe ath_pci
======= CRUCIALLY I then RE-BOOTED =======

Code:
sudo ifconfig ath0 up
iwconfig
(Previous to this I was tearing my hair out as the ifconfig ath0 up command failed unless I rebooted)

I can confirm that the instructions for getting the light working on the ACER aspire One also works fine for the Extensa 5220