Upgraded from 12.2 to 13.1 over the intenet and lost internet connection

Newly installed 13.1 indicates that my wired connection is working. . . But Firefox cannot connect and Evolution cannot fetch email. I am not the most computer literate person around, so I do not know where to start. The wireless modem (which feeds my wired OpenSuse machine) is working for my MS Windows computers. Can anyone help get me started on finding the problem? Much appreciated.
John