Why won't my ethernet connection and wireless conection work on my Dell inspiron 1521 laptop after installing Ubuntu 16.04.1 LTS?

I installed Ubuntu 16.04.1 LTS today on 3 of my desktops and one of my laptops. Everything went fine up until i got to the Dell inspiron 1521 laptop. After installing Ubuntu I found there wasn't any type of wireless connection on the computer any more. I thought it might not have installed the drivers for the wireless, so I plugged in the Ethernet cable thinking i could just download them from the Internet. That is when i noticed the Ethernet wouldn't work also. I've spent all day trying to get some sort of connection to no avail. I've never used any form of Linux before, so I am a total newbie when it comes to this. The wireless is broadcom. I came across stuff on this forum I thought would work, but when i type the commands into the terminal it just tells me the device was not found. Any help would be appreciated and thanks in advance.

2 Answers

Install network maneger

sudo apt-get install network-manager-gnome
sudo service network-manager restart

If above command did not work then

you need to turn off the secure boot and re-install bcmwl-kernel-source.

Turn off the secure boot form BIOS option

sudo apt-get purge bcmwl-kernel-source
sudo apt-get install linux-generic bcmwl-kernel-source

Reboot and done!

Do:

sudo apt-get purge bcmwl-kernel-source

Reboot and your ethernet should work, what happens when the sta driver is installed it blacklists the b43 driver for which I suspect your wireless device needs and the b44, ssb driver for the ethernet device and the above command removes the sta driver and the blacklist of the b43, b44,ssb drivers all at once.

Then do:

sudo apt-get install firmware-b43-installer

Reboot and wireless should come on. The above command installs the correct driver.