I hate that screen! If you have McAfee installed on your machine, you need to give Apache and MySQL permissions by unblocking them in McAfee's Internet applications.
Just get into the McAfee App and goto Internet Applications, find all the apps related with XAMPP, check the box and click approve. (Can find it in the system tray on botton right)
It's a simple fix but to find the answer on the web took a few hours...
McAfee also blocks TeamViewer but TeamViewer will say it a proxy error.