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).
- Can you clean install Drupal on the new system? This will take care of all requirements e.g.:
- PDO driver
- 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
- Disable boost module:
drush -y pm-disable boost
- Going to the extreme. Disable all non-core modules.