[Spangle]

Those two will stop spambots, and any automated spam, but if you are still getting spammed after using those, then it's down to human spammers, people who are paid to spam sites.

To block them you need to be a bit more clever.

There are various sites that give details of known human spammers, I use stopforumspam, they give out lists of usernames and IP's of known spammers.

Using that info, you can enter the usernames into your banned user name list, with the IP, go to your CPanel and add the IP to the "Deny IP manager" that will stop them even getting to your site, they will get a 404 persmission denied.

The problem is, as fast as you ban them, they will use a different username. so best to the IP way.