Hi, I had someone spam the hell out of my comments area. I went to the back end and highlighted them all and clicked DELETE, but nothing happened. I've since turned off the comments on the front end.

First, how else can I go about deleting all this spam. Second, where do I go to enable Comments again for the front-end: I can't seem to find it.

I had this issue and actually got a notice from google that they were going to suspend my analytic account because of all the spam. I didn't even know that one of my sites was filling up with thousands of spammed comments. What I did to delete all of them was to login to my control panel to access my Database Admin. Once logged in you'll want to go find:
jos_K2_comments

It will be here you will select it...you should see to the right of it a place to "empty" this. I clicked this and it deleted all my comments.

Only thing it didn't delete was the number of comments on my highlight of articles...they still state I have thousands in each article even though there are none.

As far as frontend...it should be listed somewhere on the parameters...which is the to the upper right icon shown when you are in the comments section of the admin area of the site.

Hope this helps!