|How are you connected to the inetrenet (DSL, CABLE, DIAL-IN)|
DIAL and Sometimes CABLE (if your router is in Bridge Mode) the Public (iNTERNET) IP address is given to your NIC (network Interface Card) of your computer.
With DSL the Public IP Address is at the outside of your Modem. Your Modem will NAT the address (translate) to the inside with a Private IP Address. THe modem wil give an IP Address in the same range to your NIC on the computer.
If their isn't one the following could be the problem
1. No cable attached or cable is defect
Check if lights are flashing on modem and PC nic
2. Your NIC in the PC is Disabled
Check at Network Connections
3. NO IP address is given to your NIC (PC)
Open dosbox and type: ipconfig / renew
check with ipconfig /all