In the XAMPP GUI click on "Config" -> "Service and Port Settings" -> "MySQL" tab -> Change Main Port to 3307 -> Save -> Save
Locate the installation file for XAMPP -> open MySQL folder -> open bin folder -> right click on "my.ini" and edit it
Change the following lines: (Line 20) Port = 3306 -> Port = 3307 (Line 28) Port = 3306 -> Port = 3307
Save the file, restart your computer, and the server should run.