Did you have this working on a testing server? Changing the store to use the sandbox versus live server has no effect on the email code. When a user registers they should receive the email. Have you tested out the user registration portion to see if you get a verification email?
Also, are you specifying to cc or bcc your email address in the admin settings for new orders? As a test you can try putting back in sandbox mode then test this out again to confirm that you are getting emails. If you have changed servers then you might need to update your SMTP server in the site settings. Please post back and let us know the results of your testing.