Still NOT RESOLVED, but here's some interesting thing I found:
I went to another computer and I do see what I consider "normal", which is what I was getting initially as far as the sections that appear upon entering the forum. I e-mailed me that web address. I went to this computer that I use, opened the e-mail and clicked on the address and THEN the usual sections appear.
However, upon using that link, I am not recognized by the forum, so I had to sign in.
But as soon as I sign in, THEN the sections DO NOT APPEAR, and I have the same problem described in original post.
So I trace the problem, and it relates to cookie of Firefox Windows XP.
I delete cookies and Saved Password (by Firefox).
So I open the forum again, I am not signed in, and I see all the sections.
And AGAIN, as soon as I am signed in, I can not see the sections.
So the issue is surely that THE FORUM restricts me from seeing those sections in the initial menu, and there's NOTHING (apparently that I can do here). So the problem is not FireFox nor my setup.
However, when signed in, I can see OWN POSTS, and via them, I can get to the General-Programming questions.
So, HOW can that restriction of the forum be removed? Can I remove it?
I don't recall doing anything that could relate to what's happening.
Thanks if anyone could help clear this out.