Enable wired and wireless network connections in Ubuntu 12.04

Recently upgraded to Ubuntu 12.04 from Ubuntu 10.04. After the upgrade, both the wired and wireless network connections didn't work.

I have summarized what I did to enable both the network connections along with the reference which I followed.

Wired Network Connection:

Step #1: Removed the package "resolvconf" and restarted the NW:

$sudo apt-get remove --purge resolvconf
$sudo /etc/init.d/networking restart

Ref: http://ubuntuforums.org/showthread.php?t=1973604

Step #2: Edited the /etc/network/interfaces file to contain only the following two lines:

auto lo
iface lo inet loopback

Ref: http://ubuntuforums.org/showthread.php?t=1943143

Wireless Network Connection:

Note: I have Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller.

Step #1: Did the following:

$sudo apt-get install linux-firmware-nonfree
$sudo modprobe -r b43
$sudo modprobe b43

Ref: http://askubuntu.com/questions/171427/wireless-isnt-working-in-12-04

Note: 
1. If you get the error "E: Unable to fetch some archives" while running the command "sudo apt-get install linux-firmware-nonfree" mentioned above, then run the command "sudo apt-get update" before doing the above step.

Ref:http://www.linuxquestions.org/questions/linux-newbie-8/icky-ubuntu-cannot-download-packages-767779/

2. If you get the following warning when you run "sudo modprobe -r b43" and "sudo modprobe b43", then just rename the files "/etc/modprobe.d/bad_list" and "/etc/modprobe.d/ndiswrapper" to "/etc/modprobe.d/bad_list.conf" and "/etc/modprobe.d/ndiswrapper.conf" respectively.

WARNING: All config files need .conf: /etc/modprobe.d/bad_list, it will be ignored in a future release.
WARNING: All config files need .conf: /etc/modprobe.d/ndiswrapper, it will be ignored in a future release.

With the above set-up the wireless network connection would be up. But on restarting the system, the wireless network connection won't be up. For the wireless connection to be up automatically, the following has to be done.

1. Edit the /etc/modprobe.d/blacklist.conf file. The /etc/modprobe.d/blacklist.conf file has the list of modules that should be prevented from loading at boot time. Comment out the following line:
• blacklist bcm43xx
2. Edit the /etc/modules file. The /etc/modules has the list of modules that would be loaded at boot time. Add the following line at the end of the file.
• b43

Ref: http://askubuntu.com/questions/90067/how-do-i-get-my-wireless-to-automatically-start-after-reboot