I was playing around with XAMPP trying out the OrangeHR open source application.
I installed XAMPP on a machine with an IIS 7 pointing to HTTP port 80. So when I tried to start apache, I encounter a conflict.
Modifying the Apache included with XAMPP to use another port is very easy. Go to the installation directory.
It usually is c:\xampp\
In c:\xampp\apache\conf look for file httpd.conf
Look for a line that says: Listen 80 and change it for the port you need. In my case Listen 78
Save the file. And restart apache and TA DA!!!