This Medion PC uses a Realtek ethernet card. Here also on NTL BB 600k. Microsoft have issed two driver updates for the Realtek cards over the past few months. A fiver sounds a bit cheap. I would expect a quality ethernet card to sell around £10 - £15. However, Novatech are a reputable firm so it should work. All ethernet cards have a unique 12 character
physical address (MAC ADDRESS) and when you change to this card from USB you may have to re-register with NTL. The cable modem notes the physical address
of the card it is first connected to. That's why if using a router its easier to clone the original mac address into the router to avoid reregistering. As you have previously been connected via USB I am not exactly sure as to the procedure. Maybe someone here will tell you or you may have to ask NTL.