I'm having a similar problem. I have two PCs now. I have one 20 foot network cable. (CAT6 I think - I don't remember) I also have no wireless capability in either (not that I'd want it) one, have already filled up all 4 ports on the router anyway, and want to link the old PC through the new PC.
I'm running XP Home on both of them, with SP1 on the old one & SP2 on the new one (which has two NICs). When I installed the motherboard drivers (EVGA 680i by the way - and while I'm here, I doubt it makes any difference, but I have ASP.NET 1.1 on the SP1 PC & ASP.NET 2.0 on the SP2 PC) & rebooted, I was automatically connected to the internet through my router (a DGL-4300 by the way; somewhat finicky) on my new PC.
So as of now, I have LAN1 running from my new (currently used to type this) PC to the router, which then runs to the modem. All the other computers connect through the router as well. I have a shorter network cable running from the 2nd port of my new PC to the network port of my old PC. Hopefully there's some way to share the internet connection properly.
When I try to enable the internet sharing on LAN1 (where this PC gets its internet connection from) it tells me this:
An error occurred while Internet Connection Sharing was being enabled.
Internet Connection Sharing cannot be enabled.
A LAN connection is already configured with the IP address
that is required for automatic IP addressing.
I'm not sure if it makes any difference, but I actually tried to enable ICS on LAN2 first, which gives me this error message:
An error occurred while Internet Connection Sharing was being enabled.
Internet Connection Sharing (ICS) cannot be enabled due to an IP
address conflict on the network. ICS requires the host be configured to use
192.168.0.1. Please ensure that no other client on the network is
configured to use 192.168.0.1.
I'm not exactly sure what bridging does, but I tried bridging the two LANs together & I didn't get any immediate results, so I deleted it while I wait to try something else in the meantime. I'm hoping that if I change the router's internal IP to 192.168.0.2 (or something) then enabling the ICS on LAN2 will work?
Any help would be greatly appreciated. I'd hate to have to buy a switch & more network cables.
EDIT: I bridged the connections again, and it worked immediately this time...?_?... Thanks for the help in the other topics though!