A Hidden Solution That Worked Easily :-)
I bolded the above in the hope that it will be the right solution for many of you with this problem.
I had done all of the changes in Settings/Discussion in the WordPress Dashboard, to make comments open. I had de-activated all plugins (only 2 anyway). I had tried different themes. I had checked lots of other forums on this. Still I got the dreaded 'Comments Closed' for all of my posts. I had thought there was going to be no solution short of getting into techie php stuff, which I have no idea about ... then the God's smiled and dispensed their infinite wisdom, to enable me to see the light :-)
So, I decided to not only read the instructions (which first involved finding them), but also managed to actually make sense of them. I hope this works for others who can't figure out what is going on.
First, I'll assume that you are allowing comments, which can be set on the page that is your website URL ending with: /wp-admin/options-discussion.php
Then, in the Dashboard click Posts, then click the Edit button for a post that you wish to adjust to allow comments.
On the top right of that post page you will see 'Screen Options' click this and it will display all kinds of hidden options. Select the Discussion and Comments boxes, along with any others you wish to see displayed. Now close 'Screen Options'.
You should now see Discussion and Comments options shown at the bottom of the page, below your post editing box. So, just select the 'allow comments' box under Discussions and you're away, Yippee!
I think this may well then set as the default for all posts, so check.
So, comments are now open on my UniversalRiches blog all I have to do is get writing articles. I find it quite interesting, I've just noticed that this topic title ends with the words "... there are NO universal settings" which has to be relevant to my blog :-)