Because the PC was connected directly to the modem and therefor saw the IP address given to it by the modem. The modem would give it a 80. address because it is known by and registered on the NTL network.
Connect to the router and you create your own little network which the router gives out the IP addreses for which is why you see 192. addresses. (
ipconfig/all
ipconfig/release
ipconfig/renew
or just try ipconfig/?
