Just today i had all my configurations for my wifi card which is
Atheros Communications Inc. AR242x 802.11abg Wireless PCI Express Adapter (rev 01) wiped of after a Hardy upgrade. So below i fixed it. But i used it also for the first time when installing Hardy fresh.

1. Open you terminal

2. Get this version of madwifi:

wget -c http://snapshots.madwifi.org/special/madwifi-hal-0.10.5.6-r3698-20080604.tar.gz

3. Untar the downloaded package:

tar xvf madwifi-ng-r2756+ar5007.tar.gz

4. Get inside the unpacked directory:

cd madwifi-ng-r2756+ar5007

5. If you haven’t compiled anything from source before on your linux then you propably need the build essential package:

sudo apt-get update && sudo aptitude install build-essential

6. Now you can build your madwifi and install the modules:
make

sudo make install
sudo modprobe ath_pci
sudo modprobe wlan_scan_sta

The last 2 commands can cause some complications on some systems. If they do check your System >> Administration >> Restricted Drivers Manager and disable atheros here. Then try again.

7. Now restart your computer and you should be able to see any aviable networks in your Network Manager.