How is drupal able to see a module even when I renamed it I ran down into a serious issue with mediabox module. After spending some time I realized its because the update has broken some functionality. I just wanted to revert back to older version. I did it by copying my local folder which is older version to the production. However it looks like drupal is still taking the older version. This I confirmed by observing the html code which is different for two versions.

I cleared cache, restarted apache. But it still somehow is getting it from the bugged code. I even removed the folder. But surprisingly it is still reading it from somewhere. I made sure I removed the cache and rebooted apache. I did this in my local machine which actually broken my site which was expected but I am wondering why its still not throwing any error even after I renamed the folder name
Drupal stores information about where to find module files in the system and registry tables.  If you want to revert an update, you'll have to replace the updated version with the old version. If you ran database updates to update the module, you'll have to disable and uninstall it first, and then re-enable it after you've replaced the module files.

If you've removed the module without disabling it, the site should break. If it's still running with the updated module, there must be another copy of it somewhere. 

If you want to know where drupal's reading the files from you can run the following SQL on the db:

SELECT filename FROM system WHERE name = 'mediabox';