That's a bit weirder than anything I've dealt with. It sounds to me vaguely like a disabled feature somewhere, but I don't know whether to look first at your browser settings or at your Psych Central ones. If I were troubleshooting it I'd want to start by figuring out whether the smilies truly weren't being inserted in your post, or whether they were actually there for others to see but your browser wasn't showing them for some reason.

-- Since you're able to see those smilies that you click on, it sounds as if where they're specifically not showing up is in your posts. By the way, do you see a smiley ---> <--- here or not, and if you do is it a picture or text characters, a [ : ] and a [ ) ]?

-- Check your PC settings. Most PC pages have a blue bar across the top with "My Profile" at the far left. Click on that link (preferably in another window or tab, so you can keep this open to refer to). In the Settings & Options section, click Edit Options. About halfway down the resulting page, under Thread Display Options, see what's checked and unchecked. I have in mine:

[ ] Show Signatures
[x] Show Avatars
[x] Show Images (including attached images and images in [IMG] code)

-- Two boxes down from Thread Display Options is Miscellaneous Options. For Message Editor Interface you might want to try, at least while you're troubleshooting this problem, the "Standard Editor -- Extra formatting controls" option. I've found it a great way to learn how the formatting codes here actually work. More often than not, WYSIWYG editors drive me crazy when I can't figure out why something that I want isn't showing up or something that I don't want, is.

-- Try typing the codes for a few smilies into a post, previewing it, and seeing what you get. I'm going to insert spaces into these examples to keep them from turning into actual smilies here:

: )
: D
: P
: hug :
: love :
: confused :

Good luck, and keep letting us know what you find. I notice you describe yourself on your profile as "computer-illiterate," but with the persistence and willingness to try stuff that you're showing, you're not going to be that way for long.

By the way, if any serious techies happen to be reading this, I notice that the little pictures in the Smilies box are coded like this:
With my extremely limited knowledge of vBCode editors, I can't make out how clicking on them results (or doesn't, in billieJ's case) in a smiley in the composer window.