Alternatively, he may have a blocker of some sort or is simply not doing anything. possibly he's left the page but his browser or your server still thinks he's connected but cant figure out what he's doing.
Also, why don't you set it up to automatically ban "hairysexteen" and his I.P.etc as soon as he registers (I don't know how difficult that would be). If worst gets worse you can just ban his ISP if it isn't a major one (which it probably isn't if its a spambot).
Also have a look
here, it's not 100% accurate, but its better than nothing.
If you manage to trace his IP range I'm sure you'd be able to block it.
BASIC programmers never die, they GOSUB and don't RETURN.