Unable to start the Apache server, Port 80 in use

Retail Pro Prism uses the Apache web server (running on port 80) to "serve up" Prism web pages. Occasionally, other software installed on the same computer can use port 80, in effect preventing the Apache web service from starting. To check if port 80 is in use, and what process is using it, you can go to the command prompt and run the following command:

Netstat -n -a -o

A list of ports being used, and the Process ID (PID) numbers that are associated with the processes using the ports are shown:

We can then determine which PID is using a particular port by visiting the "Processes" tab in the Windows Task Manager:

In this case PID 3124 is the Apache Web Server process.

It is important to note that if Microsoft IIS (Internet Information Server) was installed, it may show up as Process ID 4 (which is the system process). If you notice this, you will need to go into services and disable the World Wide Web service which runs IIS.

Some common chat programs such as Skype may use ports 80 or 443 and prevent Apache from starting.