To enable file and printer sharing on networks not using Internet Connection
Sharing, you must run the Network Setup Wizard and select the following option:
This computer connects to the Internet through another computer on my network or through a residential gateway.
If your computer is directly connected to the Internet, re-run the Network Setup Wizard and select the following option:
This computer connects to the Internet directly or through a network hub.
Other computers on my network also connect to the Internet directly or through a hub.