can't acquire network address

[modernsamurai]

My grandma just switched over from verizon internet to charter, only to find she has no connection. She's running vonage, and that works, so I know she's got internet.. but all it does is constantly try to aquire. The network address. I've done a few things to try and fix it, to no avail, but have found some strange things...
First, the ip is 0. I try to renew it through cmd, but it tels me the rpc server is unavailable.I've gone through services to find the dhcp client won't start because "the dependancy service does not exist or has been marked for deletion"
The service its talking about seems to be AFD, but its listed under device manager, though not services. I've tried loading it from a text file, as per some advice I found, bujt no change. I've tried uninstalling it, even deleting from system 32, but it just respawns. I tried reinstalling the network driver most recently, but no luck there, though still haven't restarted after that, though it didn't ask me to. I've doon a boot scan with avast but it didn't help. Power cycled countless times, even tried unhooking vonage and running it straight..
She's running xp pro sp3, any ideas? I've been at this for two days...

[modernsamurai]

Oh, and I tried hooking up a static ip, but I think I messed up with my number choice somewhere... it connected, but gave me dns errors when I tried to use the net..
And don't know if it matters, but her network adapter's a marvell yukon 8 client8e8039, that's what I just tried to update or whatever.
Also, in the event viewer I've got some errors to do with dhcp client, says it can't run without the nonexistand netbt.

[modernsamurai]

Nm, looks like I got it. Replaced netbt as well as afd did some netsh commands and it works.

[ThreadViewerAldridge]

Try using another LAN Card or reformatting your PC

[thomasbrian]

Assuming you're using WPA-PSK, this can be a symptom of the WPA auth failing. It's doesn't give you an error for the wrong WPA key, it just says it's connected, but doesn't receive anything. That includes DHCP reply packets, so you don't get an IP automatically.

Try setting up the security section of your router again and re-typing the WPA key then deleting the connection on your PC and reconnecting, again re-typing the WPA key.