You may find installing using a different method lets you move on, so try these instructions then follow the instructions below to use the latest control panel:viewtopic.php?p=179699#p179699
In the xampp installation folder you will find the version 3 control panel:
First Exit the older version and then use this instead of the older 2.5 version as it has better log window details and creates it's own log file in the xampp folder, also you will see many added features.
The latest XCPv3 versions can be found here:viewtopic.php?f=16&t=48932
Download and extract the contents into the xampp folder and overwrite when asked then use this latest version instead.
It will give you a better idea what is hogging ports 80/443 perhaps especially if you click on the Netstat button.