If you are installing Magento directly on your server, then you may get some errors while opening the installation wizard on your browser, i.e, 500 INTERNAL SERVER ERROR. Its mainly because of the wrong FILE PERMISSIONS.
The best way to solve this issue is here,
1. Download Magento Cleanup Tool
2. Unzip magento-cleanup.php to the root directory where Magento is installed.
3. Browse to http://yourdomain.com/magento/magento-cleanup.php