[Stuart]

What model/make of router do you have? Does it say it is an ADSL or DSL router? If so, it may not be compatible with NTL's network, as this needs a Cable compatible router.

Can you connect to the internet by connecting straight to the modem?

Assuming you can, you need to unplug the modem from the mains, then switch off the router. Now, plug the router into the Cable Modem. Then swtich the Cable Modem on. Wait a minute for the lights to settle, and switch the router on.

Now, plug a PC in (if possible) to the router and switch it on. I recommend this as you need to check you have a working connection before you try and use a wireless connection. That way, if the computer can attach to the net with a wired connection, but cannot with a wireless connection (which is entirely possible), we can be sure the problem is with the wireless connection, rather than the connection from the router to the Cable Modem.