Trouble Installing 12.10 on a GA-990FXA-UD3 Base Machine: Network and USB Don't Work
Solution 1:
Go to your Bios suppr or del when you turn on your computer, and when in Bios look for "network stack" and set it to "enable."
Also look for "iommu controller" and set it to "enable."
Press f10 to save and reset.
Maybe go on to the Realtek web site and download Linux drivers:
http://www.realtek.com/downloads/downloadsView.aspx?Langid=1&PNid=5&PFid=5&Level=5&Conn=4&DownTypeID=3&GetDown=false#2