My neighbor finally took the plunge to upgrade from dial-up to cable, but
cannot access the internet through it. He’s using XP Home, directly
connected to cable modem – service by Time Warner, which works fine for me
next door. His dial-up continues to work fine, but access through his
Ethernet local area connection does not. TW confirmed (with their own
laptop) that the connection & modem are good, so problem must be in his
computer.

Network Diagnostics shows pings to his IP, Default Gateway, and DHCP Server
work, but pings to DNS servers fail. Verified manually (pings to those DNS
from my computer work, so it’s not the DNS themselves). Pings to other IPs
(e.g., Google’s) also fail. Connection’s Status shows lots of packets sent,
but almost none received. Uninstalled Norton 360 with no effect. No other
security software present, Windows Firewall turned off. TCP/IP properties
and IP addresses received (DNS, DHCP) look fine (same external IP addresses
my computer gets).

Other things checked:
Boot in Safe Mode yields same results.
Device Manger shows no problems with Network Adapter or (hidden) TCP/IP
drivers.
Packet Filtering is off.
All Windows components (needed or not) are installed, all services
(needed or not) are started or on auto.
Windows SFC ran OK.

From all the sage advice I found on this board, here’s what I’ve tried
(without success):
reset TCP/IP (netsh int ip reset)
turned off ipsec service (temp)
ipconfig /flushdns
ipconfig /registerdns

So: dial-up works fine, and Ethernet HW/SW gets as far as gateway & DHCP,
but can’t get to DNS nor anything else.

I’m a bit over my head, and sure need some advice. Thanks.