ok heres my problem . i have a pc connected to a cable modem via efnet card i then have another card in same pc so theres 2 lan cards in 1 pc . i also have another pc unstairs with 1 lan card in it . i have both pc's connected together and one connected to the net . well for ages thay both worked fine and connected to the net but both pcs had to be on for the 2nd pc to connect ( thats fine no probs) but all of a sudden to 2nd pc came up with limited or no connection icon in the task bar ive tryed everything i know and cant get the 2nd pc to connect . ive shared the 2nd pc 's stuff and can read it from the 1st pc . so that would mean both lan cards are fine and the cable works wouldnt it? can ne 1 help please .. thx

Do you use a hub or switch, or are you only using a crossover cable? Is there any point where people can walk over any of the cables or roll over them with a chair (even under a carpet)? Are there any staples holding the cabling in place? If so, it'd be a good idea to start replacing cables and checking connections.

Also, are the lights coming up on the back of the network cards? Do you have a laptop and a crossover cable that you could use to check the operation of the network card in the second PC (with the singel ethernet card)?

Could be the NIC went bad - it happens...voltage spike or static electricity could have fried the nic. Just plain old age could do it too.

Either way, you should look into getting a router and using it instead of the 2 network setup. It will give you a lot less problems and will be MUCH easier to add more/newer PC's to your home network.

Even wireless hardware is very cheap anymore... and as long as you have some basic security in place (no SSID broadcase and WPAPSK alone is a big step in the right direction) it will provide you with a great amount of flexibility.