The Boxing Dog wrote
My question is, how do I protect myself from spam...
If you click on the profile of the user, you – as an admin – will see a link to ban the user. If the user keeps coming back with different accounts, then you can report the problem to us and we will take care of him/her.
The Boxing Dog wrote
... and is there a way to have the people that go to my forum have to register before they can post a thread?
Yes. Click on "Options > Users > Change permissions" and make sure that only "Registered" users can create new topics and reply to posts. If you have questions, please let us know.