The first thing to check is to see if the NIC card is
showing up. Without the hardware being checked
and confirmed to be running then checking other
things is not productive.
Check ifconfig and see if there are 2 entries, one for
lo and one for eth0 or wlan0 or something in that range.
Is this a wireless or wired connection?
Please post the NIC card name,make and model number.
Bigpaws