I have a friend who has a Cable modem with a LAN connection and he wishes to use a WiFi Router that has an ADSL modem to enable WiFi on his Cable Internet. Can anyone help with what I need to do to enable the router to work with the cable modem as I'm sure it will need something like Bridging and DHCP alterations. Thanks.

A combined "Router & ADSL Modem" cannot be used as a router with Cable broadband, although you may be able to use it as a wireless access point to allow one computer to connect wirelessly.

You would go into the routers settings (by connecting to it by ethernet cable and typing its IP address into a web browser), disable its DHCP server and configure its "wireless" settings (SSID, Channel number, WEP/WPA encryption etc.). Then power everything off, including the Cable Modem which should be left without power for three or four minutes - this is IMPORTANT so that it loses the association between the existing connection (recognised by its MAC address) and the IP address it has allocated to it. Connect an ethernet cable between the Cable Modem and one of the router's LAN ports and (for the moment) a second ethernet cable between a second LAN port in the router and the PC.

Power on the Cable Modem and, when fully booted, power on the router. Finally boot the PC. The Cable Modem should recognise a new connection and allocate a different IP address to it. As the router is acting as a simple network switch, it should pass your "public" WAN addresses (which would normally be a router's WAN settings) directly through to the PC's "Local Area Connection" and you should have internet access. If that worked, remove the Router-PC ethernet cable and connect "wirelessly".

I don't guarantee this will work, because this sort of arrangement is normally carried out by connecting to an existing router and when doing so, the second router's own IP address is changed to an unused address in the main router's subnet. You can't do this because you're connecting directly to an ISP's router and cannot take one of their addresses.

If you (or friend) already have the necessary hardware, try it and see.

NOTE: When swapping to Cable Modem connection back again, you must repeat the process of powering off for several minutes to lose the association with the router's MAC address.

An additional thought - as you're going to be disabling the router's DHCP server, when connecting to it by ethernet cable, give your Local Area Connection a fixed IP address in the same range as the router's IP address. Otherwise you might lose the connection when the DHCP server is disabled. When finished configuring the router, return the PC's Local Area Connection to getting both IP and DNS server addresses automatically, so it gets the addresses allocated by the ISP.

Terrific answer. If I get stuck at any point I'll repost, but many thanks as I'm sure things will go well.