As a newbie, I starting to build my website using Wordpress (3.3.1) and Atahualpa (3.7.3) for the first time. I managed doing more or less what I want, except for a few small problems.

One of which is that I have decided to get rid of the comment area on my posts and pages. After failing to do this on my own, I searched the forums, followed directions, and managed to get rid of the comment area on all NEW posts and pages. My problem now is that the comment area on all posts that have already been published refuses to disappear. I searched the forums, but couldn't find any solution to this. Can someone please help me?
Thank you

the fastest way would be to use the 'comment' section of The WordPress dashboard and go in and delete all existing comments.

If you just want to hide the comments you could add the following to the CSS inserts option

#respond,
.commentlist,
#comments { display: none !important;}

Thanks for the response, but it's not the comments themselves that I can't get rid of (I have no comments at the moment). It's the whole "Leave a Reply" area. It's still there on all the published posts. I can't get rid of that whole section.

go look at the 'Edit POST/PAGE INFO ITEMS' options for footers

I've tried that already.

Under "footer: single post pages" I have:
%date('F jS, Y')% | %tags-linked('Tags: ', ', ', ' | ')% Category: %categories-linked(', ')% %edit('|', 'Edit this post', '')%

Footer: Homepage, Multi Post Pages, and "page" pages, are all totally empty.

Again, I would like to state again for clarity, that the problem exists only with the posts that were published BEFORE I tried to get rid of the reply/comment area. All NEW posts are OK, and do not show the reply/comment area.
Thank you

Do you use a caching plugin / have you emptied your browser cache? You might be seeing something what isn't there anymore ;-)

I emptied the browser's cache many times, and even used a different browser on a different computer to check it out, but it didn't help.
I was actually using a caching plug-in (W3 Total Cache). I cleared the cache on all categories, but it didn't help. I even DE-activated the plug-in - but still no go. That comment/reply section just doesn't want to leave.

what is the url? when I add in the code above, the coment area goes away. as 'hospitalera ' said, if you have a caching plugin, deactivate it.

Here is a sample post:
http://www.myappliancetips.com/gas-grill-buying-guide/

As I said in my last post, I have already deactivated the plug-in. But it didn't help. I'll look to see if there could be some other plug-in which is caching the pages.

You don't have the css I suggested in the CSS Inserts.

Oh. I apologize. I thought that was just to get rid of the comments themselves.
I inserted what you suggested and it WORKED.
Thank you so much.