Lost lan internet connection after Trusty update (2/1/16)

I have Trusty Tahr 14.04 LTS on 2 computers (& several devices) that are connected to the internet via my home LAN. Everything has been fine until 2/1/16 when i let the desktop computer update. I did not use it afterward, but this morning (2/2/16) when i really needed internet the desktop could not find the internet. Neither Firefox nor Chromium could make a connection. My Ubuntu LTS laptop is on the same net where the updates were NOT loaded...works just fine on the internet (as well as all the other devices). Is possible to undo the update? I have worked with Linux and Unix a little in the long past so i need a newby solution that doesn't require internet until the bug is fixed. please help!