Troubleshoot Drupal by stripping it down to safe mode

Symptoms

Transfer your Drupal instance from 1 system to another 1. Then, on the latter system, it doesn't work(e.g. page not found, can't log in, url screw up, etc).

Troubleshooting tips

• Can you clean install Drupal on the new system? This will take care of all requirements e.g.:
  • PDO driver
  • GD
  • Enable mod_rewrite
• Clear all cache: drush cc all
• Disable clean URLs: drush vset clean_url 0 --yes
  • If you run Drupal in subdirectory, then see https://www.drupal.org/node/43783
  • https://www.drupal.org/node/15365
• Disable boost module: drush -y pm-disable boost
• Going to the extreme. Disable all non-core modules.