Running windows xp home edition sp2 i have a wanadoo wireless and talk live box connected to my main computer via lan this works perfectly. however the wireless adaptor on my second computer is very intermitant i was wondering whether i could add a network pci card to connect my 2 computers together with out interfering with the internet connection on my main computer
If you are going to connect the two computers directly, without interfering with the existing cabled connection to the router, you need to install a *second* network adapter in the PC that connects to the router, a network adapter in the second PC and link them with a "crossover" network cable. If you need internet access in the second PC, you would have to enable Internet Connection Sharing on the first PC's actual connection to the router.
This setup wouldn't make much sense because a router should provide the internet access for all networked computers. You would probably be better plugging a network switch in to the router to provide additional LAN ports.