Troubleshoot the Internet
You may be
able to communicate with every computer in your LAN, but still not
connect to the Internet. There may be an error message indicating that
you only have Local Access.
The Network and Sharing Center may also display a big,
red X between your network and the Internet.
When you double click the red X, the Windows Network
Diagnostics will ping the Primary DNS Server by sending a
small packet to their IP address and listening for the reply.
Before you change your setup or reset the network
adapter, confirm:
Are there lights on the Cable router?
Is the CAT5 cable plugged into the Cable router, as well
as the network card on the back of your computer?
Is everything plugged in and turned on?