I cannot connect with internet through broadband

I use Internet by broadband connection in my netbook and its operating system is Windows 7. Sometimes I find a problem in the connection. I can not connect with the Internet. It shows an error message. The message is:
Error 651: The modem (or other connecting device) has reported an error.
If you continue to receive error messages, you can enable logging for analysis.
Why the problem occurs and how can I solve the problem?

