network just says no

just installed vista on my dell xps 600.
but i can't seem to go much further with anything till i can get my network and i'net connection sorted.
doesn't want to pick up an ip adress automagicaly at all. putting in the details my router should be handing to it it takes them but can't do anything with them as still gives me the limited or no connectivity (says its connected to the network but not the internet)
diagnosing gives limited or no connectivity but not much else help. tried resetting the network connection, reset my router and modem. put in the ip and stuff manualy, still fails.
its showing as connected to the network but when i try to ping to any of the other machines it gives an error code 1231, cant seem to find anything relevant to that. loopback works okay though. other machines on network cannot ping sys either.
network port is nforce4 port running on drivers with vista v6.1.7.110
any help is highly appreciated :)

I'm having the same problem... i'm using a NFORCE2 IGP + MCP-T chipset on a Biostar iDeq 200N SFF PC. When I go to the LAN connection status it shows media state as 'enabled', but no connectivity for IPv4. It shows speed as 100 Mbps and several hundred sent packets over the last hour, but 0 received.
My other PC's connect to the network and internet just fine through a Netgear WGR614 v4 router.
I've tried all the basic little 'repair' things, I even tried setting a static IP (which I used to do instead of DHCP back in the day, so iIknow how to do it.) and it still gets 0 packets received.
I know the card and cable work fine, I still have Windows XP 32-bit installed on another partition and it works just fine.
Everything looks fine... it just, wont work.