I have a Dell inspiron 17 and I installed Ubuntu yesterday and when I logged in (I was originally on windows 8) there were no WiFi connections at all...
I've tried everything and I can't seem to find a solution...
I have a Dell Inspiron 17, and I had the same problem. It is due to the fact that the machine uses a wifi card that requires a proprietary driver. It is easy to fix. First, you will need to connect your machine to your internet router by a cable. Then in a terminal window, enter the command
In the window that appears, select the "Additional Drivers" tab. The screen shows "Searching for available drivers ...". After a minute or so, you should see your wifi card listed, with two options, like this:
Choose the first option, and click Apply Changes.
You will then just need to press F2 to enable (unlock) the wifi card, and then it should all work. When you click on the wifi icon in the toolbar, you should see a list of available networks. Select yours, and enter its password when prompted. You can then disconnect your cable from the router.
Please insert the command
sudo lshw -c network
If your network device is the BCM43___ then follow the thread:
It might contain something useful to you, I have the same problem but with the Bluetooth functionality of B43___ board.