how do i stop spammers comign on my forum

Well, outsourcing/subcontracting can never be stopped. You can however ban 95% of spam with these methods because current spammers won't bother to outsource on just any website. Just because a method can be circumvented does not mean it will (the lazy/cheap spammer) and does not mean you should just leave the doors wide open.

 

You could also place and IP Ban list from the most common spam countries. Then check around too, I have seen some places that will update IP list on the regular that will give the ip of the new bots. Then you cam update your forum and that will block most of the crappy bots.