After installing LXDE on Ubuntu 16.04, cannot connect to internet

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I installed LXDE desktop environment so I could get desktop version instead of terminal. All was well (I could ping and do sudo apt-get) when I just had ubuntu 16.04 running but then I wanted to use LXDE so I could get a gui and make things easier but know now I cannot ping anymore. I can ssh to 192.168.7.2 from my mac and serial connect to the UART debug controller but I cannot use anything that uses the internet to work. I even tried to share my Mac's internet connection but that does not work as well! (It used to, ONLY ONCE when I first setup the board. I had to connect serially to /dev/tty.usbmodem1423 but now that doesn't even show up!) I don't know what's going on with these boards.....