Spencer Finnell

You want to stop the posts in the category from showing up in the lists of posts? Or you want the category to not show up in say, a list of categories? Or both?

You need to be able to either access an online control panel (like cPanel) or be able to log into FTP. Your host should give you accees to both of those.

You can switch hosts, but you need to be able to log into backup your data.

Looks like a plugin might be trying to add some code to the bottom of the post. Do you have any plugins activated? If so, deactive them all and see if the problem goes away. Looks like it might be some sort of social plugin.

W3 Cache probably isn’t the problem, but I’d guess Guest blogger could be. Read about disabling plugins without admin access.

What theme are you using? Do you want this image to be a post-specific image, like in the Twenty Ten theme? or are you talking about an image for a logo.

It looks like your comment form is posting to a bad URL. /wordpress/wp-comments-post.php is not correct.

Replace action="/wordpress/wp-comments-post.php" with action="<?php echo get_option('siteurl'); ?>/wp-comments-post.php"

Widgets that are coded with the new Widget API can be used more than once by default. You don’t need a plugin.

If you’re nervous, make sure you have a backup of your database and a copy of your theme.

By visiting this page and clicking “Save” at the bottom, you tell WordPress that you have updated your permalinks, and it then knows it needs to update the database with the new settings.

So basically WordPress should update the .htaccess for you (I’m pretty sure; maybe someone else will chime in.)

You can stop the Visual Editor from loading by going to “Users > Your Profile” and checking “Disable the visual editor when writing.”

If you installed MAMP, and it is running, you should be able to access it through https://localhost/phpmyadmin

Invisible as in a completely blank page, or are just certain elements missing?

Are you using the same thing you were before you upgraded?

Do you have a wp-comments-post.php in your WordPress install root directory?

Is it a custom widget? Widgets coded with the new Widget API should be able to be used more than once.

There could be many pages/things in the CSS. Where do you want the posts to be centered? And by centered do you mean just the text, or the entire post itself?

A link to the site would be much more helpful.

If you haven’t made too many modifications yet, you can delete the theme, and reinstall a fresh copy of it, which will undo any things you changed, and errors you created.