One way to handle "Port 80 in use by "Unable to open process" with PID 4!" error

This frustrating message is displayed if there is port contention between an existing program and the new program you are trying to install.

For example, I wanted to install Apache, MySQL and PHP using the XAMPP cross-platform web server stack. I was frustrated by various erros that showed up which includes the 'Port 80 in use by Unable to open process with PID 4!'. It could be Port 443 as well. I am using Windows 7 64bit Ultimate edition OS and XAMPP version 1.8.3.

The PID refers to a port being used by the system. After various tweaks found a  way to start APACHE and the other programs. The XAMPP Control Panel may have a bug. Read here for details...

http://hodentekhelp.blogspot.com/2014/02/on-installing-apache-on-windows-7-64bit.html