To expand on what @fischi said, first step to troubleshooting is switch to the default theme (twentyeleven) and disable all plugins. If your content shows up, turn plugins back on one by one until you either find the offending plugin or they’re all on. If you get them all back on and the content still shows, you know the problem is somewhere in your theme.
To generate a list of theme files used for any page, put this code at the end of your functions.php:
// Returns a list of files used to generate the page. Best called in footer.php before </body>
function get_template_name () {
echo '<pre>';
foreach ( debug_backtrace() as $called_file ) {
print_r($called_file['file']);
echo '<hr />';
}
echo '</pre>';
}
This will output a list of all php files used to generate a page, and you can easily see which template files are being called (look for \wp-content\themes\mytheme\something.php).
Edited to add: You will need to call this function somewhere. I prefer to include it in footer.php, right before </body> like this:
<?php
if (is_user_logged_in()) {
get_template_name() ;
}
?>
You can also add this line after the function in functions.php: add_action('wp_footer', 'get_template_name'); but that will generate it for everyone, not just the logged in user. You can also use is_admin() instead of is_user_logged_in() if you want to restrict it even further.