What files are used for sending User Confirmation Emails?

[pr0zac]

Ok, nothing I've tried has worked. I'm confident that everything is set up correctly, but yet I'm still not seeing user confirmation Emails being sent out after a new signup (using CCBill as the gateway). I've tried disabling all other plugins too. My last resort before a completely fresh re-install is just re-uploading the file(s) that are used for sending out the new user confirmation Email. Does anybody know what these are so I can just do a quick re-upload of them? Thanks in advance.