Have you tried:
-clearing cache in your browser before viewing the updated page? To clear cache in your browser, press clrl+f5 keys simultaneously. Also, try different computers / different browser.
-contacting the webserver if the database server is online / if they have problem at their end, or they made any changes to your account, or if there are any limitations/restrictions, etc . Also check with them if you need to upgrade the hosting account in order to install and run your verson of the WordPress?
-make sure all files/folders got uploaded to the rihgt location.
-Checking your wp-config.php file settings for the database name, and the host name (e.g., “localhost” Vs. something else)?
-deactivating ALL plugins temporarily to narrow down and possibly fix the problem . If the problem goes away, activate them individually to find the culprit?
If you don’t have access to your admin area, try deactivating them manually via FTP or phpMyAdmin.
-switching to the default theme (“twentyten”) for a moment by renaming your current theme’s folder in wp-content/themes. The idea is to force WordPress to fall back to the default theme to rule out any theme-specific issue?
If you don’t have access to your admin area, then access your server via FTP or SFTP or whatever file management application your host provides.
-If the above steps do not resolve the issue, Download WordPress again and replace your copies of everything EXCEPT the wp-config.php file and the /wp-content/ directory with fresh copies. This should replace your core files without changing your content and settings in wp-config.php file and the /wp-content/ directory.
Note that some uploaders may not overwrite files reliably, so delete the original files before replacing them.
-if that does not resolve the issue, try increasing memory available for php.
