iamitp, check if your router is detected first
$ifconfig -a and if eth0 appears
If u know the ip address , gateway and dns server do this (as root
$ ifconfig eth0 <enter ip here> up
$ route add default gw <enter gateway ip here>
$cat >> /etc/resolv.conf
nameserver <enter your dns ip here>
$ ping
www.yahoo.com to check if it works..