Well I just setup a Ubuntu machine that i'm thinking about giving my sister. But of course I ran into a problem which usually happens running a Linux operating system. The Realtek RTL8111 LAN/Ethernet port would take way to long to connect or wouldn't connect at all. So the following command comes from a user named praseodymium over at http://forum.ubuntuusers.de/topic/lan-karte-funktioniert-nicht/#post-3005217 which looks like a German related Ubuntu Support site.
The following commands will help you resolve your issue if you have the Realtek RTL8111 LAN port which is on M2A-VM motherboards and possibly a few others. Type the following commands one by one in the Terminal.
sudo apt-get install --reinstall linux-headers-$(uname -r) build-essential dkms
tar xvf r8168-8.038.00.tar.bz2 cd r8168-8.038.00/
sudo sh ./autorun.sh
Once complete you will be able to connect to the internet as soon as you login.