Re: 500 internal server error on xampp
I've heard that most Mac users find MAMP better than XAMPP, but others say the latter works fine, so let's skip that for the moment.
Have you checked the includes/configure.php file and the admin/includes/configure.php file to make sure the paths are set up properly?
Also, make sure permissions are set according to the install directions on your files and folders.
Finally (gotta say it just to be complete) make sure you've removed the install directory.
Breakfast: the most important donut of the day.