If your using 100baseT and you connect the 10BaseT NIC on it. If you have the dial-up adapter on your PC and you set the IP same as your NIC IP subnet. I get no response. Use it to setup a responer and sender to check to Data Link Layer and Phyiscal Layer is OK or not. Try pinging yourself.
Rx lights are off.
Just can't see the other computer or its folders from either machine. Both machines can ping themselves, but not each other. This just happened to me tonight. One that you are using may be a cross over witch would still give you link lights but may not let you ping. Well I solved the problem.