Unplugging the router and modem does not change the situation. The WinsockXPFix utility hasn't fixed it either.
I have been able to get around it by manually entering an IP address within the range of the router. However, I don't want to do that. It would keep me from visiting a local hotspot if I wanted to take my laptop to a public place.
I have a similar problem with a second laptop (compaq presario) running Vista Home Basic. None of the three options for repair work. Once again, a manually entered IP address works, but I want to use automatic IP address.