Default XAMPP install will attempt to install Apache as a service configured to run on Port 80. But, if you’re like me, and have IIS already installed and running, for whatever reason, you’ll probably want to configure XAMPP to run Apache on a different port.
Allow XAMPP to co-exist with IIS configured to run on Port 80, and Apache to run on Port 8080 (and SSL running on Port 4499):
• Search for “Listen 80″, change to “Listen 8080″
• Search for “ServerName localhost:80″, change to “ServerName localhost:8080″
• Search for “Listen 443″, change to “Listen 4499″
• Search for “”, change to “”
• Search for “ServerName localhost:443″, change to “ServerName localhost:4499″
Then, you should be able to start Apache successfully through the XAMPP control panel.