We just upgraded our site at www.fremantlechamber.com.au to the latest version of Drupal and CiviCRM 4.6.18
Now when we try to register for an event, the credit card details are not appearing and noone can pay for registration.
I had a look and can you entire billing block is indeed MIA.
1) get into the Event Registration Config and try re-adding the Payment Processor - re-save
2) check for errors in your ConfigAndLog/ when you load this form
EDIT - more thoughts:
3) check the Payment Processors their config - and create a (Test) Contribution page where you run a transaction with a fake credit card
4) (in general) check the Manage Extensions screen and look if there are any upgrades for your Payment Processor (of course this only applies to those which are not baked in core)