The other computer is working fine but the faulty one,
although it  can access usenet and email, cannot access the web using
Chrome, IE or Safari.  However Opera and Firefox work ok.
(I  disabled the  firewall but this made no difference.)
Presumable there are some settings in the browsers that I have
configured differently. I would be grateful if someone could tell me
what I should be looking for.
TIA
Reg
Here is the diagnostic that IE provided for me:
Last diagnostic run time: 07/12/10 11:53:03 Gateway Diagnostic
Gateway
info	The following proxy configuration is being used by IE:
Automatically Detect Settings:Disabled Automatic Configuration Script:
Proxy Server:socks=127.0.0.1:7070 Proxy Bypass
list:plimus.com,www.plimus.com,regnow.com,www.regnow.com,
info	This computer has the following default gateway entry(ies):
192.168.1.1
info	This computer has the following IP address(es): 192.168.1.101
info	The default gateway is in the same subnet as this computer
info	The default gateway entry is a valid unicast address
info	The default gateway address was resolved via ARP in 1 try(ies)
info	The default gateway was reached via ICMP Ping in 1 try(ies)
info	Skipped gateway connectivity check because of IE proxy
configuration
DNS Client Diagnostic
DNS - Not a home user scenario
info	Using Web Proxy: yes
No DNS servers
DNS failure
HTTP, HTTPS, FTP Diagnostic
HTTP, HTTPS, FTP connectivity
warn	HTTP: Error 12029 connecting to www.microsoft.com: A
connection with the server could not be established
warn	FTP (Passive): Error 12029 connecting to ftp.microsoft.com: A
connection with the server could not be established
warn	HTTP: Error 12029 connecting to www.hotmail.com: A connection
with the server could not be established
warn	HTTPS: Error 12157 connecting to www.microsoft.com: An error
occurred in the secure channel support
warn	FTP (Active): Error 12029 connecting to ftp.microsoft.com: A
connection with the server could not be established
warn	HTTPS: Error 12157 connecting to www.passport.net: An error
occurred in the secure channel support
error	Could not make an HTTP connection.
error	Could not make an HTTPS connection.
error	Could not make an FTP connection.
info	Redirecting user to support call
Wireless Diagnostic
Wireless - Service disabled
Wireless - User SSID
Wireless - First time setup
Wireless - Radio off
Wireless - Out of range
Wireless - Hardware issue
Wireless - Novice user
Wireless - Ad-hoc network
Wireless - Less preferred
Wireless - 802.1x enabled
Wireless - Configuration mismatch
Wireless - Low SNR
IP Configuration Diagnostic
Invalid IP address
info	Valid IP address detected: 192.168.1.101
IP Layer Diagnostic
Corrupted IP routing table
info	The default route is valid
info	The loopback route is valid
info	The local host route is valid
info	The local subnet route is valid
Invalid ARP cache entries
action	The ARP cache has been flushed
WinSock Diagnostic
WinSock status
info	All base service provider entries are present in the Winsock
catalog.
info	The Winsock Service provider chains are valid.
info	Provider entry MSAFD Tcpip [TCP/IP] passed the loopback
communication test.
info	Provider entry PCTOOLS over [MSAFD Tcpip [TCP/IP]] -> MSAFD
Tcpip [TCP/IP] passed the loopback communication test.
info	Provider entry MSAFD Tcpip [UDP/IP] passed the loopback
communication test.
info	Provider entry PCTOOLS over [MSAFD Tcpip [UDP/IP]] -> MSAFD
Tcpip [UDP/IP] passed the loopback communication test.
info	Provider entry RSVP UDP Service Provider passed the loopback
communication test.
info	Provider entry RSVP TCP Service Provider passed the loopback
communication test.
info	Connectivity is valid for all Winsock service providers.
Network Adapter Diagnostic
Network location detection
info	Using home Internet connection
Network adapter identification
info	Network connection: Name=Local Area Connection, Device=Realtek
RTL8168C(P)/8111C(P) PCI-E Gigabit Ethernet NIC, MediaType=LAN,
SubMediaType=LAN
info	Ethernet connection selected
Network adapter status
info	Network connection status: Connected
HTTP, HTTPS, FTP Diagnostic
HTTP, HTTPS, FTP connectivity
warn	HTTP: Error 12029 connecting to www.microsoft.com: A
connection with the server could not be established
warn	FTP (Passive): Error 12029 connecting to ftp.microsoft.com: A
connection with the server could not be established
warn	HTTP: Error 12029 connecting to www.hotmail.com: A connection
with the server could not be established
warn	HTTPS: Error 12157 connecting to www.microsoft.com: An error
occurred in the secure channel support
warn	FTP (Active): Error 12029 connecting to ftp.microsoft.com: A
connection with the server could not be established
warn	HTTPS: Error 12157 connecting to www.passport.net: An error
occurred in the secure channel support
error	Could not make an HTTP connection.
error	Could not make an HTTPS connection.
error	Could not make an FTP connection.
Lists that there is a proxy in there, have you checked the proxy config? 
Firefox uses its own config, IE uses the windows one. No idea on opera 
or chrome since 2 browsers is 1 to many for me.
>
>Lists that there is a proxy in there, have you checked the proxy config? 
>Firefox uses its own config, IE uses the windows one. No idea on opera 
>or chrome since 2 browsers is 1 to many for me.
Thanks Richard
Chrome had an option checked to use a proxy for the LAN.
I unchecked that and it fixed all three browsers.