Above the box in which I put this text is a row of buttons: B, i, u, Quote …
If I am tempted to use the first button to make text bold it does not have this effect. Instead it inserts “open-square-bracket b close-square-bracket” before, and “open-square-bracket solidus b close-square-bracket” afterwards.
I finally press the “submit” button and check what appears, just in case it has worked as I hoped, but it never does. Am I doing something wrong? When other people read my post does it look right to them?
How very strange! When I select the word “bold” and press the first button on the toolbar, I get this: bold.
In the text area where I’m typing, I see “open-square-bracket b close-square-bracket” before the word, and “open-square-bracket solidus b close-square-bracket” afterwards, just as you’ve described, but when I preview the post I see the word in bold (and when I submit the post it looks the same as the preview). I see markup in the OP to this thread, but bold text in my quoted copy of it.
Below the box is a checkbox for “Disable BBCode”
You had enabled that. I edited your post to re-enable it, and fixed some other issues with code and a list. Please check it again to see if it makes sense.
Also: check your posting defaults in the User Control Panel to see if they are still set to whatever you prefer.