No LBC - Computer Question

My other computer will not connect to the internet. The DSL modem and router 
are fine. The 10/100 card shows to be working properly when I run the 
troubleshooter wizard. The driver is current and loaded. The message says that 
a cable is unplugged... All cables checked and operable. 

Any guesses? I even tried a system restore to an earlier date when everything 
worked properly, no good.

Kent
1960 Bugeye