Problem with shortcodes

hello,

I just started using wordpress today so I’m totally new, however I have some experience as programmer.

Now my problem….

I decided to install a contact form pluggin, tried 3 or 4 of them and always get the same problem, the post shows the shortcode instead the form.

Some thing you may want to know

– I don’t have any other pluggin active
– I reinstalled WP (same DB) and no luck
– This Could be the key: When I installed the fist pluggin (fast secure contact form) it worked just fine, I refreshed thr page couple times and the form was there, but suddenly stopped working and from there I can’t use any of them.

Hope you guys can help me, thanks in advance.