just installed ubuntu 14.04 on Dell Latitude d620 and no wired or wireless connection. Hardware: Dell Wireless 1490 Duel Band WLAN Mini-Card. Broadcom BCM4311 802.11a/b/g [14e4:4312]. Kernel driver:wl. I tried to install Synaptic package manager(downloaded it to a USB, then connect USB to 14.04 system) I don't think I am using the package manager right, or mabe I'm not install the drivers right. Any have a clue? And please don't say to just download the package.....I've done that 20 times and it doesn't register. Thanks for any insight you can provide.
You installed a wrong driver for the wireless adapter. That probably is also the reason why Ethernet does not work as well.
Remove the wrong driver by running in terminal
sudo apt-get purge bcmwl-kernel-source
After reboot the Ethernet should work. Then connect to the internet and install firmware by
sudo apt-get install firmware-b43-installer
If Ethernet does not work for some reason, use this answer to install the firmware offline.