Hi,
I have three computers let us name 1,2 and 3 for reference. All have WinXP with SP2. Now when I connect computers 1 and 2 as a network they work fine. Also, when I connect computers 2 and 3, with the same cable that I used for 1 and 2, they work fine as a network. but, the problem is when I connect computers 1 and 3, with the same cable as used above, I get a message in the LAN icon stating that "A network cable is unplugged". This message appears in both the computers i.e. 1 and 3 and cannot be connected. I don't understand why and cannot form a network here.
Can somebody help me ?

Have you eliminated that the a port on the hub/switch/concentrator is bad?

Are you using a cross-over cable or a switch/hub?

I directly connect with the cross-over cable and no hub etc. I don't understand which computer to check for the problems 1 or 3( as described in the original thread) because they always form a network with the computer 2 when connected separately with the later.

Try doing this while no cable is plugged in:
at command prompt type IPCONFIG
note all 3 pc's IP address's, it may be possible that 2 have the same ip??

I tried the way you told Jenkins. Both the PC (1 and 3) say "Media State .............:Media Disconnected" under Ethernet adapter Local Area Connection

I have recently had this problem, approximately. It is a strange one, I admit. I would lay some money on the cable being at fault. Yes, I know, it works in one configuration. But mine did, too. And when I replaced the cable on the connection that did not work, it worked fine. And it´s still working as we speak. Reality can be strange, sometimes.

It could be as simple as some of the pins loose, or the pins bent in one of the NICs. Change cable, if that doesn't work try a different NIC.

You need to get a hub so that all 3 can be connected, anyway. You can find them for as little as $10 so it's not a biggie.

Almost as soon as I hit post reply I remembered that it will not show stuff under ipconfig w/ no cables attchd. But ? still remains, are 2 IP's the same and bucking each other, also may be a good idea to manually config each ip address. One way to see what needs to be put in (manually) is to leave it as "Obtain an IP automatically", connect to pc's (that work) and do an ipconfig again. You should now get a IP, a subnet mask and maybe even a gateway address. Note these down, The last set of digits will need to be different for each pc's ip address, the subnet mask and gateway will be same on each pc.
ie
IP Address......:192.168.1.100
Subnet Mask...:255.255.255.0
Gateway........:192.168.1.1
Could have one as above, next as 192.168.1.101 as ip, mask and gateway would stay same on all 3 pc's.
My question to everyone now is, When using a crossover cable <> 2 pc's and auto ip addressing, how does an ip get assigned and who does it (no DHCP Server there)????