If you are working from a Dell computer on Ubuntu, you might have noticed that you cannot connect to your internet wirelessly. This is because the driver for your network card has not been installed. Here are 3 steps to fix it: 1) Plug in an ethernet cable (a wired connection to the router). 2) Open a Terminal (Ctrl + Atl + T) 3) Type the following commands (hitting enter after each
sudo apt-get install linux-firmware-nonfree
sudo modprobe -r b43 && sudo modprobe b43
And your problem shall be solved. Hope this helps.
If that fails, this link should help.