There is a problem with the connection to the phone line or there is a problem with your modem.
Check the connection to the phone line
Check the cable connection to the modem–if you are using a desktop computer with an internal modem, make sure the telephone cable is plugged into the back of the computer in the port called “line.” It should not be plugged into the ports called "phone” port or “Ethernet.”
Check the service in the phone jack–make sure that the phone jack in your wall is working properly. Plug a telephone into the same phone jack and lift the handset to see if you hear the dial tone. If you do not hear the dial tone the phone jack is not working properly and you should contact your phone company for repair.
Check the telephone cable–try using the same cable with your telephone or replacing it with a cable that you know works.
Reset your modem
If you are using a desktop computer with an internal modem, shut down your computer and leave it off for at least 5 seconds (from the Start menu, select Shut Down). Then restart your computer and try to connect again. If you are using an external modem, leave your computer turned on while you turn your modem off and then on.
Make sure you are using the correct modem
Check if you have more than one modem installed. In Windows, go to the Control Panel folder and double-click Modems (95/98/ME) or Phone and Modem Options (2000/XP). If you have more than one modem installed, try selecting one of the other modems and then connecting again.
If you still cannot connect to the Internet, your modem might be damaged, or there might a problem with your system configuration. Contact the manufacturer or a local computer repair facility. If there is a problem with your modem, our Customer Support representatives will not be able to help you fix it.