In the web based admin util, hit the 'administration' tab and then the 'diagnostics' page. You can try to ping / tracert to
www.ntlworld.com from there.
The other thing to check (prob first) is the 'Status' tab, which should show what NTL IP is assigned - if any.
Can you confirm what LED's are lit on the front of the router & which ports on the back you have connected to what.