Fundamental problem with 10/100 base-T

[JohnE]

Okay, a short history lesson. Prior to buying my latest motherboard I used a Belkin wireless LAN to connect my 2 machines in a peer-to-peer network (1 x desktop machine, 1 x laptop). When I bought the new motherboard (about 4 months ago) I carried on using it successfully, even though both my machines now have onboard 10/100 base-T. Eventually I overcame my laziness and went to my local computer shop and bought a crossover cable which I installed after removing the wireless LAN. It worked brilliantly and was wonderfully fast - until I switched the machines off and tried to turn them on again the following morning. The machines turn on alright, but the cable network just refuses to work.

I've figured out that it must be a really fundamental problem because I can't even ping one computer from the other. The hardware appears to be working and both machines do notice if the cable is removed, for example. Both machines claim that the link is working at 100mbits/s but absolutely no communication takes place. Sometimes I got occasional problems like this with the old wireless LAN and I found that if I set the IP addresses to 10.0.0.1 and 10.0.0.2 respectively, that would usually start it working again and I could then change the settings - however, that's not working with the cable setup.

Both machines use Windows XP Home Edition and I've even tried the setup wizard (which fails to complete on both machines). The really annoying thing is that it worked perfectly for the first day! I've tried re-installing the wireless LAN (which still works) but nothing seems to bring the cable network to life.

There's a possible clue in all of this. If I run 'ipconfig /renew' from the command line, both machines report "Unable to contact your DCHP server". Does that mean anything or isn't it relevant in peer-to-peer networking?

I've been plugging away at this for two whole days without success. Please help someone....