Well, since we can’t test that, download WordPress again and delete then replace your copies of the /wp-admin/ and /wp-includes/ directories with fresh copies from the download.
If that doesn’t work, there’s a possibility that you may be encountering unreported PHP memory allocation errors.
Here are four ways to increase PHP’s memory allocation:
1. If you have access to your PHP.ini file, change the line in PHP.ini
If your line shows 32M try 64M:
memory_limit = 64M ; Maximum amount of memory a script may consume (64MB)
2. If you don't have access to PHP.ini try adding this to an .htaccess file:
php_value memory_limit 64M
3. Try adding this line to your wp-config.php file:
Increasing memory allocated to PHP
define('WP_MEMORY_LIMIT', '64M');
4. Talk to your host.
And, if that doesn’t work, you may be encountering unreported internal server errors. Internal server errors are usually described in more detail in the server error log. If you have access to your server error log, generate the error again, note the date and time, then immediately check your server error log for anything useful. If you don’t have access to your server error log, ask your hosting provider to look for you.
