Go to a command prompt and type
ipconfig /all
and press enter.
Do you see an IP address assigned to this adapter? Also the default gateway,
and DNS servers? If so, can you:
Ping your default gateway IP address successfully? If so, can you:
Ping one of your DNS servers' IP addresses successfully? If so, can you:
Ping a host on the internet such as
www.yahoo.com and even if you don't get
replies, see an IP address returned? If so -
Check your IE settings - tools, internet options, connections, and select
'never dial' - and under LAN settings, make sure there's no tickbox next to
proxy server.