Hello,

This is an interesting situation you have there. I would check the router's web config thingy and see if there is an auto disconnect if there isn't any traffic.

If you can get your hands on a packet sniffer, you could also see if the router is doing something like re-configuring the IP addresses (DHCP) every 10 minutes or so.

Try this: Open the Mac and ping the PC. Let it ping for at least 15 minutes (don't worry -- won't hurt anything). If the connection survives, I think you have a timeout problem. If the pings start dropping, then there could be a problem.

Because the Cable Lan is working, I think your individual computers are fine.

Christian