blank pages are often caused by plugin or theme function conflicts, so if you have access to your admin panel, try deactivating all plugins. If you don't have access to your admin panel, try manually resetting your plugins, using ftp rename plugins folder to plugins_hold and create a blank plugins folder If that resolves the issue, delete blank plugins folder and rename original back to plugins reactivate each one individually until you find the cause.
If that does not resolve the issue, try switching default theme (WordPress 3.0 and higher) to rule-out a theme-specific issue. If you don't have access to your admin panel, access your server via FTP or SFTP, navigate to /wp-content/themes/ and rename the directory of your currently active theme. This will force the Default theme Twenty Ten theme (WordPress 3.0 and higher) to activate and hopefully rule-out a theme-specific issue.
If that does not resolve the issue, it's possible that a .htaccess rule could be the source of the problem. To check for this, access your server via FTP or SFTP and rename the .htaccess file. If you can't find a .htaccess file, make sure that you have set your FTP or SFTP client to view invisible files.
If you weren’t able to resolve the issue by either resetting your plugins and theme or renaming your .htaccess file,then try this to know what file is causing the problem
First check wp-config.php if you have any blank space before
if there is none then try and add this code in next line after
error_reporting(E_ALL); ini_set('display_errors', 1);
In addition, add the following code above
/* That’s all, stop editing! Happy blogging. */ :
define( 'WP_DEBUG', true);
if you this line in wp-config.php file just change false to true
See what error you get.
and replace the files that are giving error from fresh WordPress download.