When you create the menu in Appearance > Menus look at the Screen Options. You can select Posts there
It was that easy. Thank you very much keesiemeijer. You really made my day.
You would really make my day square 2 if you would also answer the second question :). I’ve seen in some blogs that they don’t have the text Posted in ‘a certain category’, they just have the name. How can I make the category now show?
Are you using the theme twentyten? What theme are you using?
Delete this from archive.php, index.php, search.php and single.php:
<h3>
Posted by <span><?php the_author() ?></span> | Posted in <span><?php the_category(', ') ?></span> | Posted on <?php the_time('d-m-Y') ?>
</h3>
Thank you very much keesiemeijer for your help.
No problem. Glad you got it solved.