<<< Today I bought the USB Adapter (Netgear WG111T) to make the PC wireless & the Netgear WGT624 Wireless Router >>>
I'm not sure what you are doing here because, as far as I know, the WGT624 is a "stand-alone" router (i.e. no combined ADSL Modem) which is normally suitable for use with Cable broadband - NTL or Telewest.
Are you "daisy chaining" two routers so that the Netgear's WAN port is plugged into a LAN port in the Voyager? Otherwise, how is the Netgear connecting to the internet?