Some other application is using port 80. You could change the IIS configuration to use a different port number. Or, you could stop the service or application that is using port 80. Run the command "netstat –a –o" to identify the process ID of a process listening on port 80. You can then use Task Manager or the "tasklist" command-line tool to identify the process name given the process ID.
This was first published in May 2004