You say you have "NTL cable box to main PC & router for laptop." Do you meen from the NTL box into the router by wire then the main PC connects to the router by wire and the laptop by wireless?
You should be able to enter the web based setup pages for the router by entering its address in your browser (this should be in its instructions I am not familier with this router) then look for the wireless security this should be WEP or WPA depending on what it supports WPA is better and follow instructions for setup.
you should also look for the SSID broardcast and change it's name to something that you will recognise but hides the make of the router because it will be easier to crack the security if the make is known.
Change the password that allows you to enter the setup pages because agin default ones are easy to find out.