Error 500 (Internal Server Error) After Clearing Cache I truncated cache_block and cache_bootstrap tables in Drupal database (I don't know if its okay to truncate cache tables) and after that my site went down. 

I am getting HTTP Error 500 that says 


  The website encountered an error
  while retrieving www.drupalwebsite.com. It may be down for maintenance
  or configured incorrectly.


Before truncating those tables, my site was working fine. Is there any way to get it back to working??




  UPDATE -


I cleared all other cache tables too... 

WEBSERVER LOGS -


  [Thu Dec 27 02:51:24 2012] [warn] [client *IP_Address*] mod_fcgid: stderr: PHP Fatal error: Call to undefined function ctools_include() in /var/www/vhosts/*my_site_name*/drupal/sites/all/modules/views/views.module on line 62
Somehow your site has entered a broken state since the Views module depends on ctools but it's not enabled.

What you need to do to fix it is to:


Enable the ctools module in the database, by running the following SQL UPDATE system SET status = 1 WHERE name = 'ctools';
Truncate all the cache tables in your database.
(Might not be needed) run $ drush rr, requires drush and the registry rebuild extension.
Run $ drush cc all requires drush.


Going through the above list should fix your site. Messing with your sites cache table can be a bit dangerous if you don't know what you are doing since drupal caches what modules it needs to load for performance.

You can read more about and download drush and registry rebuild on drupal.org.