have you tried connecting the PC by cable to the router
What firewall / security suite or anti-virus do you currently have on the PC - or you have ever had on the PC in the past - any trial ware - like Norton, Mcafee , AVG , Webroot etc
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TCP/IP stack repair options for use with Vista/Windows 7
Start> Programs> Accessories> and
right click on Command Prompt, select "Run as Administrator" to open a command prompt box
(A new dialogue box - black with white font, will appear on the screen ):
In the command prompt window that opens, type the following commands:
Note: Type only the text in bold and red for the following commands.
Reset WINSOCK entries to installation defaults:
netsh winsock reset catalog and press
enter
Reset IPv4 TCP/IP stack to installation defaults.
netsh int ipv4 reset reset.log and press
enter
Reset IPv6 TCP/IP stack to installation defaults.
netsh int ipv6 reset reset.log and press
enter
ReStart (reboot) the machine.
If you receive the message
The requested operation requires elevation.
Then please open the command prompt as administrator - as requested above
Start> Programs> Accessories> and
right click on Command Prompt, select "Run as Administrator" to open a command prompt box
(A new dialogue box - black with white font, will appear on screen ):
Please note and post back - if you receive the following message :-
Access is Denied
please post back the results in a reply here - its important we know that these commands have worked correctly and not produced any errors
right click in the command prompt box
select all
enter
control key + C key - to copy
then reply here and
control key + V to paste
Details also here
http://support.microsoft.com/kb/299357
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