mate check firstly what the proper modelnumber is (F5D72*** for router or F5D7130 for Access Point)
if its an Access point you wont be able to have both computers online at the same time as NTL only give out 1 ip address at a time.
if its a router, disconnect the power from the modem for 5 mins and plug in the belkin router, after the 5 mins connect the NTL to the power again and you should be up and running (you can see that if the connected light on the router is on not blinking)
in useful IT info I posted a link to a belkin setup guide for all the products so you might just have to give that a go
link if you cant find it or having a friday lazy feeling:
http://www.cableforum.co.uk/board/sh...ad.php?t=36788